Lease Liabilities Maturities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Maturity of Lease Liabilities, Operating Leases [Abstract]
Remainder of 2019	$ 42
2019		$ 61
2020	56	53
2021	42	40
2022	35	33
2023	27	26
Thereafter	73	65
Total lease payments	275
Less: Interest	(27)
Total	$ 248	$ 278
Operating lease, Weighted-average remaining lease term (years)	6 years 4 months 24 days
Operating lease, Weighted-average discount rate, percent	3.20%
Maturity of Lease Liabilities - Finance Leases [Abstract]
Remainder of 2019	$ 11
2020	14
2021	7
2022	7
2023	7
Thereafter	14
Total lease payments	60
Less: Interest	(5)
Total	$ 55
Finance lease, Weighted-average remaining lease term	6 years 7 months 6 days
Finance lease, Weighted-average discount rate, percent	3.40%