CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Parenthetical) - USD ($) $ in Millions |
12 Months Ended | ||
|---|---|---|---|
Dec. 31, 2017 |
Dec. 31, 2016 |
Dec. 31, 2015 |
|
| Other Comprehensive Income (Loss), Unrealized Gain (Loss) on Derivatives Arising During Period, Tax | $ 2 | $ 2 | $ 2 |
| Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax | 4 | 4 | 4 |
| Derivative Instruments, Gain (Loss) Reclassified from Deferred Accounts into Income, Tax | 4 | 4 | 4 |
| Other Comprehensive Income (Loss), Defined Benefit Plan, Gain (Loss) Arising During Period, Tax | $ 0 | $ 0 | $ 0 |