Statements Of Consolidated and Combined Equity and Partners' Capital - USD ($)
$ in Millions
Total
Parent
Noncontrolling Interest
Accumulated Other Comprehensive Loss
Limited Partner
Common Units
Limited Partner
Subordinated Units
Beginning Balance (Predecessor) at Dec. 31, 2014   $ 4,188.0        
Beginning Balance at Dec. 31, 2014 $ 4,171.3   $ 0.0 $ (16.7) $ 0.0 $ 0.0
Income (Loss), Including Portion Attributable to Noncontrolling Interest | Predecessor   42.7        
Income (Loss), Including Portion Attributable to Noncontrolling Interest 42.7   0.0 0.0 0.0 0.0
Other Comprehensive Income (Loss) | Predecessor   0.0        
Other Comprehensive Income (Loss) 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 tax liabilities not assumed by Columbia OpCo | Predecessor [1]   1,232.5        
Predecessor net tax liabilities not assumed by Columbia OpCo [1] 1,222.2   0.0 (10.3) 0.0 0.0
Contributed/Noncontributed Net Parent Investment Adjustments | Predecessor [2]   (7.7)        
Contributed/Noncontributed Net Parent Investment Adjustments [2] (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   4,188.0        
Beginning Balance at Dec. 31, 2014 4,171.3   0.0 (16.7) 0.0 0.0
Income (Loss), Including Portion Attributable to Noncontrolling Interest 383.6          
Other Comprehensive Income (Loss) [3],[4] 0.8          
Predecessor net tax liabilities not assumed by Columbia OpCo [3],[4],[5]       (10.3)    
Ending Balance (Predecessor) at Sep. 30, 2015   0.0        
Ending Balance at Sep. 30, 2015 7,561.3   6,308.5 (4.1) 955.5 301.4
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
Income (Loss), Including Portion Attributable to Noncontrolling Interest | Predecessor   0.0        
Income (Loss), Including Portion Attributable to Noncontrolling Interest 340.9   289.3 0.0 27.9 23.7
Other Comprehensive Income (Loss) | Predecessor   0.0        
Other Comprehensive Income (Loss) 0.7   0.6 0.1 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 [6]   0.0        
Purchase of additional interest in Columbia OpCo [6] 0.0   424.4 0.0 (227.1) (197.3)
Distributions to the noncontrolling interest in Columbia OpCo | Predecessor   0.0        
Distributions to the noncontrolling interest in Columbia OpCo (569.9)   (569.9) 0.0 0.0 0.0
Quarterly distributions to unitholders | Predecessor   0.0        
Quarterly distributions to unitholders (26.0)   0.0 0.0 (13.9) (12.1)
Transfers From Parent | Predecessor   0.0        
Transfers From Parent 1.3   1.1 0.0 0.2 0.0
Ending Balance (Predecessor) at Sep. 30, 2015   $ 0.0        
Ending Balance at Sep. 30, 2015 7,561.3   6,308.5 (4.1) 955.5 301.4
Beginning Balance at Dec. 31, 2015 7,576.7   6,318.2 (4.0) 958.5 304.0
Income (Loss), Including Portion Attributable to Noncontrolling Interest 331.4   283.1 0.0 27.2 21.1
Other Comprehensive Income (Loss) 1.7 [4]   1.4 0.3 0.0 0.0
Purchase of additional interest in Columbia OpCo     0.0      
Distributions to the noncontrolling interest in Columbia OpCo (373.9)   (373.9) 0.0 0.0 0.0
Quarterly distributions to unitholders (56.9)   0.0 0.0 (30.4) (26.5)
Ending Balance at Sep. 30, 2016 $ 7,479.0   $ 6,228.8 $ (3.7) $ 955.3 $ 298.6
[1] Reflects the non-cash elimination of all historical current and deferred income taxes other than Tennessee state income taxes that continue to be borne by the Partnership post-IPO, as well as associated regulatory assets and liabilities.
[2] Reflects the removal of amounts related to Crossroads Pipeline Company, CPGSC, Central Kentucky Transmission Company and 1% of the 50% interest in Hardy Storage that were included in the Predecessor but were not contributed to the Partnership, as well as the inclusion of CNS Microwave, which was not part of the Predecessor.
[3] All amounts prior to the IPO are net of tax.
[4] Amounts in parentheses indicate debits.
[5] 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.
[6] Represents the purchase of an additional 8.4% limited partner interest in Columbia OpCo, recorded at the historical carrying value of Columbia OpCo's net assets after giving effect to the $1,168.4 million equity contribution. This decreases common unitholders and subordinated unitholders equity by the same amount it increases noncontrolling interest because the Partnership's purchase price for its additional 8.4% interest in Columbia OpCo exceeded book value.