Fair Value of Financial Assets and Liabilities - Recurring (Details) - Fair Value, Measurements, Recurring [Member] - Significant Other Observable Inputs (Level 2) [Member] - USD ($) $ in Millions	Sep. 30, 2018	Dec. 31, 2017
Assets:
Deferred compensation investments in mutual funds	$ 17	$ 18
Total	20	21
Liabilities:
Deferred compensation plan liabilities	18	19
Total	40	44
Foreign Exchange Forward [Member]
Assets:
Foreign currency contracts - assets	2	2
Liabilities:
Foreign currency contracts - liabilities	16	25
Foreign currency options [Member]
Assets:
Foreign currency contracts - assets	1	0
Liabilities:
Foreign currency contracts - liabilities	0	0
Interest Rate Swap [Member]
Assets:
Interest rate swaps	0	1
Liabilities:
Interest rate swaps	$ 6	$ 0