Fair Value of Financial Assets and Liabilities - Recurring (Details) - Fair Value, Measurements, Recurring [Member] - Significant Other Observable Inputs (Level 2) [Member] - USD ($) $ in Millions	Mar. 31, 2018	Dec. 31, 2017
Assets:
Interest rate swaps	$ 0	$ 1
Deferred compensation investments in mutual funds	18	18
Total	30	21
Liabilities:
Interest rate swaps	4	0
Deferred compensation plan liabilities	18	19
Total	28	44
Foreign Exchange Forward [Member]
Assets:
Foreign exchange contracts - forwards	9	2
Liabilities:
Foreign exchange contracts - forwards	6	25
Options Held [Member]
Assets:
Foreign currency options	$ 3	$ 0