Fair Value of Financial Assets and Liabilities - Recurring (Details) - USD ($) $ in Millions		Dec. 31, 2017	Dec. 31, 2016
Assets:
Current swaps	[1]	$ 1	$ 4
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member]
Assets:
Current swaps		1	4
Deferred compensation investments in mutual funds		18	15
Total		21	107
Liabilities:
Foreign exchange contracts - forwards		25	39
Deferred compensation plan liabilities		19	17
Total		44	56
Fair Value, Measurements, Recurring [Member] | Significant Other Observable Inputs (Level 2) [Member] | Foreign exchange contracts - forwards [Member]
Assets:
Foreign exchange contracts - forwards		$ 2	$ 88

[1] Fair value adjustments include the following: (i) fair value adjustments to debt associated with terminated interest rate swaps, which are being amortized to interest expense over the remaining term of the related notes; and (ii) changes in fair value of hedged debt obligations attributable to movements in benchmark interest rates. Hedge accounting requires hedged debt instruments to be reported inclusive of any fair value adjustment.