Statements Of Consolidated and Combined Equity and Partners' Capital - USD ($)
$ in Millions
Total
Parent
Noncontrolling Interest
Accumulated Other Comprehensive Loss
Limited Partner
Limited Partner
Common Units
Limited Partner
Subordinated Units
Beginning Balance (Predecessor) at Dec. 31, 2012   $ 3,758.3          
Beginning Balance at Dec. 31, 2012 $ 3,739.5   $ 0.0 $ (18.8)   $ 0.0 $ 0.0
Net Income (Loss) Attributable to Parent | Predecessor   266.9          
Net Income (Loss) Attributable to Parent 266.9   0.0 0.0   0.0 0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | Predecessor   0.0          
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent 1.1   0.0 1.1   0.0 0.0
Partners' Capital Account, Distributions | Predecessor   (113.0)          
Partners' Capital Account, Distributions (113.0)   0.0 0.0 $ 0.0 0.0  
Net Transfers (To) From Parent | Predecessor   5.4          
Net Transfers (To) From Parent 5.4   0.0 0.0   0.0 0.0
Net Income | Predecessor 266.9            
Total comprehensive income | Predecessor [1] 1.1            
Ending Balance (Predecessor) at Dec. 31, 2013   3,917.6          
Ending Balance at Dec. 31, 2013 3,899.9   0.0 (17.7)   0.0 0.0
Net Income (Loss) Attributable to Parent | Predecessor   269.1          
Net Income (Loss) Attributable to Parent 269.1   0.0 0.0   0.0 0.0
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent | Predecessor   0.0          
Other Comprehensive Income (Loss), Net of Tax, Portion Attributable to Parent 1.0   0.0 1.0   0.0 0.0
Net Transfers (To) From Parent | Predecessor   1.3          
Net Transfers (To) From Parent 1.3   0.0 0.0   0.0 0.0
Net Income | Predecessor 269.1            
Total comprehensive income | Predecessor [1] 1.0            
Ending Balance (Predecessor) at Dec. 31, 2014 4,171.3 4,188.0          
Ending Balance at Dec. 31, 2014 4,171.3   0.0 (16.7)   0.0 0.0
Net Income | Predecessor   42.7          
Net Income 42.7   0.0 0.0   0.0 0.0
Total comprehensive income | Predecessor   0.0          
Total comprehensive income 0.1   0.0 0.1   0.0 0.0
Contribution of capital from parent | Predecessor   1,217.3          
Contribution of capital from parent 1,217.3   0.0 0.0   0.0 0.0
Predecessor Net Liabilities Not Assumed By Subsidiary | Predecessor   1,232.5          
Predecessor Net Liabilities Not Assumed By Subsidiary 1,222.2   0.0 (10.3)   0.0 0.0
Contributed/Noncontributed Net Parent Investment Adjustments | Predecessor   (7.7)          
Contributed/Noncontributed Net Parent Investment Adjustments (7.7)   0.0 0.0   0.0 0.0
Ending Balance (Predecessor) at Feb. 11, 2015   6,672.8          
Ending Balance at Feb. 11, 2015 6,645.9   0.0 (26.9)   0.0 0.0
Beginning Balance (Predecessor) at Dec. 31, 2014 4,171.3 4,188.0          
Beginning Balance at Dec. 31, 2014 4,171.3   0.0 (16.7)   0.0 0.0
Net Income 530.2            
Total comprehensive income [1] 1.3            
Predecessor Net Liabilities Not Assumed By Subsidiary [1],[2]       (10.3)      
Ending Balance (Predecessor) at Dec. 31, 2015   0.0          
Ending Balance at Dec. 31, 2015 7,576.7   6,318.2 (4.0)   958.5 304.0
Beginning Balance (Predecessor) at Feb. 11, 2015   6,672.8          
Beginning Balance at Feb. 11, 2015 6,645.9   0.0 (26.9)   0.0 0.0
Net Transfers (To) From Parent | Predecessor   0.0          
Net Transfers (To) From Parent 4.4   3.6 0.0   0.5 0.3
Net Income | Predecessor   0.0          
Net Income 487.5   413.5 0.0   39.9 34.1
Total comprehensive income | Predecessor   0.0          
Total comprehensive income 1.2   1.0 0.2   0.0 0.0
Allocation of Net Investment to Unitholders | Predecessor   (6,672.8)          
Allocation of Net Investment to Unitholders 0.0   6,185.7 0.0   0.0 487.1
Allocation of Accumulated Other Comprehensive Loss To Noncontrolling Interest | Predecessor   0.0          
Allocation of Accumulated Other Comprehensive Loss To Noncontrolling Interest 0.0   (22.7) 22.7   0.0 0.0
Net proceeds from IPO | Predecessor   0.0          
Net proceeds from IPO 1,168.4   0.0 0.0   1,168.4 0.0
Purchase of additional interest in Columbia OpCo | Predecessor   0.0          
Purchase of additional interest in Columbia OpCo 0.0   424.4 0.0   (227.1) (197.3)
Distribution to the noncontrolling interest in Columbia OpCo | Predecessor   0.0          
Distribution to the noncontrolling interest in Columbia OpCo (687.3)   (687.3) 0.0   0.0 0.0
Limited Partners' Capital Account, Distribution Amount | Predecessor   0.0          
Limited Partners' Capital Account, Distribution Amount (43.4)   0.0 0.0   (23.2) (20.2)
Ending Balance (Predecessor) at Dec. 31, 2015   $ 0.0          
Ending Balance at Dec. 31, 2015 $ 7,576.7   $ 6,318.2 $ (4.0)   $ 958.5 $ 304.0
[1] All amounts prior to the IPO are net of tax. Amounts in parentheses indicate debits.
[2] Reflects the non-cash elimination of all historical current and deferred income taxes other than Tennessee state income taxes that will continue to be borne by the Partnership post-IPO.