Goodwill and Other Intangible Assets (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Definite-lived intangible assets
Carrying amount of indefinite-lived intangible assets	$ 646	$ 647
Carrying amount of indefinite-lived intangible assets - trade names	69	67
Gross Carrying Amount	567	572
Accumulated Amortization	(451)	(434)
Net Carrying Amount	116	138
Definite-lived intangible assets acquired during the year, amount assigned	$ 9
Definite-lived intangible assets acquired during the year, weighted-average amortization period	5 years
Aggregate amortization expense for definite-lived intangible assets	$ 30	27	$ 28
Estimated intangible amortization expense for next five years:
2019	28
2020	22
2021	19
2022	16
2023	13
Customer relationships [Member]
Definite-lived intangible assets
Gross Carrying Amount	184	194
Accumulated Amortization	(134)	(124)
Net Carrying Amount	50	70
Contracts [Member]
Definite-lived intangible assets
Gross Carrying Amount	215	222
Accumulated Amortization	(193)	(194)
Net Carrying Amount	22	28
Other [Member]
Definite-lived intangible assets
Gross Carrying Amount	168	156
Accumulated Amortization	(124)	(116)
Net Carrying Amount	$ 44	$ 40