Basis of Presentation - Revision of Financial Statements (Details) (USD $)
In Millions, unless otherwise specified
 3 Months Ended 9 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2015
Mar. 31, 2014
Jun. 30, 2014
Condensed Combined Statements of Operations          
Revenues $ 526.4 $ 501.1 $ 1,560.4 $ 1,470.9  
Cost of revenues 321.8 304.9 956.6 900.5  
Selling, general and administrative expenses 105.5 96.1 321.9 303.4  
Total expenses 427.9 401.0 1,313.1 1,203.9  
Operating earnings 98.5 100.1 247.3 267.0  
Other income, net 1.8 0.6 4.7 1.8  
Earnings before income taxes 91.0 100.5 232.6 268.1  
Provision for income taxes (32.8) (29.1) (89.0) (86.9)  
Net earnings 58.2 71.4 143.6 181.2  
Less: net earnings attributable to noncontrolling interest 1.9 1.8 5.9 5.2  
Net earnings attributable to CDK 56.3 69.6 137.7 176.0  
Condensed Combined Statement of Comprehensive Income          
Currency translation adjustments     (40.1) 30.4  
Other comprehensive income (23.2) 6.4 (40.1) 30.4  
Comprehensive income 35.0 77.8 103.5 211.6  
Less: comprehensive income attributable to noncontrolling interest       5.2  
Comprehensive income attributable to CDK 33.1 76.0 97.6 206.4  
Current assets:          
Accounts receivable, net 352.8   352.8   310.7
Other current assets 185.1   185.1   164.1
Total current assets 906.4   906.4   918.2
Property, plant and equipment, net 85.3   85.3   82.6
Other assets 245.4   245.4   233.1
Assets 2,509.3   2,509.3   2,598.6
Current liabilities:          
Accrued expenses and other current liabilities 161.5   161.5   158.0
Total current liabilities 475.7   475.7   497.5
Deferred income taxes 73.3   73.3   76.5
Other liabilities 35.6   35.6   32.5
Total liabilities 1,745.3   1,745.3   789.3
Equity:          
Net parent company investment 0   0   1,712.2
Accumulated other comprehensive income 45.6   45.6   85.7
Total CDK stockholders' equity 752.1   752.1   1,797.9
Noncontrolling interest 11.9   11.9   11.4
Total equity 764.0   764.0   1,809.3
Total liabilities and equity 2,509.3   2,509.3   2,598.6
Adjustments to reconcile net earnings to cash flows provided by operating activities:          
Depreciation and amortization     57.1 39.6  
Deferred income taxes     (2.0) (14.1)  
Other     (5.9) (7.1)  
Changes in operating assets and liabilities, net of effects from acquisitions and divestitures of businesses:          
Increase in accounts receivable     (55.6) (36.0)  
Increase in other assets     (19.1) (11.7)  
(Decrease)/increase in accrued expenses and other liabilities     14.6 (24.7)  
Net cash flows provided by/(used in) operating activities     160.2 142.6  
Cash Flows from Investing Activities:          
Capital expenditures       (30.4)  
Net cash flows (used in)/provided by investing activities     (7.8) (63.2)  
Cash Flows from Financing Activities:          
Dividend payments of CVR to noncontrolling owners     (5.4) (8.0)  
Net cash flows provided by/(used in) financing activities     (163.8) 10.2  
Combined Statement of Equity          
Total equity 764.0   764.0   1,809.3
Net Parent Company Investment          
Condensed Combined Statements of Operations          
Net earnings     39.0    
Equity:          
Total equity 0   0   1,712.2
Combined Statement of Equity          
Total equity 0   0   1,712.2
Accumulated Other Comprehensive Income          
Condensed Combined Statement of Comprehensive Income          
Currency translation adjustments     (40.1)    
Equity:          
Total equity 45.6   45.6   85.7
Combined Statement of Equity          
Total equity 45.6   45.6   85.7
Total CDK Stockholders' Equity          
Equity:          
Total equity         1,797.9
Combined Statement of Equity          
Total equity         1,797.9
Noncontrolling Interest          
Condensed Combined Statements of Operations          
Net earnings     5.9    
Equity:          
Total equity 11.9   11.9   11.4
Combined Statement of Equity          
Total equity 11.9   11.9   11.4
As Reported          
Condensed Combined Statements of Operations          
Revenues   500.5   1,469.3  
Cost of revenues       899.1  
Selling, general and administrative expenses       308.3  
Total expenses       1,207.4  
Operating earnings       261.9  
Other income, net       0.1  
Earnings before income taxes   98.3   261.3  
Provision for income taxes       (86.3)  
Net earnings   69.3   175.0  
Less: net earnings attributable to noncontrolling interest   0   0  
Net earnings attributable to CDK   69.3   175.0  
Condensed Combined Statement of Comprehensive Income          
Currency translation adjustments       30.4  
Other comprehensive income       30.4  
Comprehensive income       205.4  
Less: comprehensive income attributable to noncontrolling interest       0  
Comprehensive income attributable to CDK       205.4  
Current assets:          
Accounts receivable, net         299.1
Other current assets         164.6
Total current assets         907.1
Property, plant and equipment, net         109.9
Other assets         205.5
Assets         2,587.2
Current liabilities:          
Accrued expenses and other current liabilities         154.2
Total current liabilities         493.7
Deferred income taxes         76.6
Other liabilities         43.9
Total liabilities         797.0
Equity:          
Net parent company investment         1,704.6
Accumulated other comprehensive income         85.6
Total CDK stockholders' equity         1,790.2
Noncontrolling interest         0
Total equity         1,790.2
Total liabilities and equity         2,587.2
Adjustments to reconcile net earnings to cash flows provided by operating activities:          
Depreciation and amortization       51.2  
Deferred income taxes       (14.7)  
Other       (0.7)  
Changes in operating assets and liabilities, net of effects from acquisitions and divestitures of businesses:          
Increase in accounts receivable       (34.9)  
Increase in other assets       (9.5)  
(Decrease)/increase in accrued expenses and other liabilities       (32.8)  
Net cash flows provided by/(used in) operating activities       149.0  
Cash Flows from Investing Activities:          
Capital expenditures       (44.8)  
Net cash flows (used in)/provided by investing activities       (77.6)  
Cash Flows from Financing Activities:          
Dividend payments of CVR to noncontrolling owners       0  
Net cash flows provided by/(used in) financing activities       18.2  
Combined Statement of Equity          
Total equity         1,790.2
As Reported | Net Parent Company Investment          
Equity:          
Total equity         1,704.6
Combined Statement of Equity          
Total equity         1,704.6
As Reported | Accumulated Other Comprehensive Income          
Equity:          
Total equity         85.6
Combined Statement of Equity          
Total equity         85.6
As Reported | Total CDK Stockholders' Equity          
Equity:          
Total equity         1,790.2
Combined Statement of Equity          
Total equity         1,790.2
As Reported | Noncontrolling Interest          
Equity:          
Total equity         0
Combined Statement of Equity          
Total equity         0
Hardware | Adjustments          
Condensed Combined Statements of Operations          
Revenues   0.6   1.6  
Cost of revenues       1.4  
Selling, general and administrative expenses       0.3  
Total expenses       1.7  
Operating earnings       (0.1)  
Other income, net       1.7  
Earnings before income taxes   0.4   1.6  
Provision for income taxes       (0.6)  
Net earnings   0.3   1.0  
Less: net earnings attributable to noncontrolling interest   0   0  
Net earnings attributable to CDK   0.3   1.0  
Condensed Combined Statement of Comprehensive Income          
Currency translation adjustments       0  
Other comprehensive income       0  
Comprehensive income       1.0  
Less: comprehensive income attributable to noncontrolling interest       0  
Comprehensive income attributable to CDK       1.0  
Current assets:          
Accounts receivable, net         11.6
Other current assets         (0.5)
Total current assets         11.1
Property, plant and equipment, net         (27.3)
Other assets         27.6
Assets         11.4
Current liabilities:          
Accrued expenses and other current liabilities         3.8
Total current liabilities         3.8
Deferred income taxes         (0.1)
Other liabilities         0
Total liabilities         3.7
Equity:          
Net parent company investment         7.6
Accumulated other comprehensive income         0.1
Total CDK stockholders' equity         7.7
Noncontrolling interest         0
Total equity         7.7
Total liabilities and equity         11.4
Adjustments to reconcile net earnings to cash flows provided by operating activities:          
Depreciation and amortization       (11.6)  
Deferred income taxes       0.6  
Other       (1.2)  
Changes in operating assets and liabilities, net of effects from acquisitions and divestitures of businesses:          
Increase in accounts receivable       (1.1)  
Increase in other assets       (2.2)  
(Decrease)/increase in accrued expenses and other liabilities       0.1  
Net cash flows provided by/(used in) operating activities       (14.4)  
Cash Flows from Investing Activities:          
Capital expenditures       14.4  
Net cash flows (used in)/provided by investing activities       14.4  
Cash Flows from Financing Activities:          
Dividend payments of CVR to noncontrolling owners       0  
Net cash flows provided by/(used in) financing activities       0  
Combined Statement of Equity          
Total equity         7.7
Hardware | Adjustments | Net Parent Company Investment          
Equity:          
Total equity         7.6
Combined Statement of Equity          
Total equity         7.6
Hardware | Adjustments | Accumulated Other Comprehensive Income          
Equity:          
Total equity         0.1
Combined Statement of Equity          
Total equity         0.1
Hardware | Adjustments | Total CDK Stockholders' Equity          
Equity:          
Total equity         7.7
Combined Statement of Equity          
Total equity         7.7
Hardware | Adjustments | Noncontrolling Interest          
Equity:          
Total equity         0
Combined Statement of Equity          
Total equity         0
NCI | Adjustments          
Condensed Combined Statements of Operations          
Revenues   0   0  
Cost of revenues       0  
Selling, general and administrative expenses       (5.2)  
Total expenses       (5.2)  
Operating earnings       5.2  
Other income, net       0  
Earnings before income taxes   1.8   5.2  
Provision for income taxes       0  
Net earnings   1.8   5.2  
Less: net earnings attributable to noncontrolling interest   1.8   5.2  
Net earnings attributable to CDK   0   0  
Condensed Combined Statement of Comprehensive Income          
Currency translation adjustments       0  
Other comprehensive income       0  
Comprehensive income       5.2  
Less: comprehensive income attributable to noncontrolling interest       5.2  
Comprehensive income attributable to CDK       0  
Current assets:          
Accounts receivable, net         0
Other current assets         0
Total current assets         0
Property, plant and equipment, net         0
Other assets         0
Assets         0
Current liabilities:          
Accrued expenses and other current liabilities         0
Total current liabilities         0
Deferred income taxes         0
Other liabilities         (11.4)
Total liabilities         (11.4)
Equity:          
Net parent company investment         0
Accumulated other comprehensive income         0
Total CDK stockholders' equity         0
Noncontrolling interest         11.4
Total equity         11.4
Total liabilities and equity         0
Adjustments to reconcile net earnings to cash flows provided by operating activities:          
Depreciation and amortization       0  
Deferred income taxes       0  
Other       (5.2)  
Changes in operating assets and liabilities, net of effects from acquisitions and divestitures of businesses:          
Increase in accounts receivable       0  
Increase in other assets       0  
(Decrease)/increase in accrued expenses and other liabilities       8.0  
Net cash flows provided by/(used in) operating activities       8.0  
Cash Flows from Investing Activities:          
Capital expenditures       0  
Net cash flows (used in)/provided by investing activities       0  
Cash Flows from Financing Activities:          
Dividend payments of CVR to noncontrolling owners       (8.0)  
Net cash flows provided by/(used in) financing activities       (8.0)  
Combined Statement of Equity          
Total equity         11.4
NCI | Adjustments | Net Parent Company Investment          
Equity:          
Total equity         0
Combined Statement of Equity          
Total equity         0
NCI | Adjustments | Accumulated Other Comprehensive Income          
Equity:          
Total equity         0
Combined Statement of Equity          
Total equity         0
NCI | Adjustments | Total CDK Stockholders' Equity          
Equity:          
Total equity         0
Combined Statement of Equity          
Total equity         0
NCI | Adjustments | Noncontrolling Interest          
Equity:          
Total equity         11.4
Combined Statement of Equity          
Total equity         $ 11.4