Goodwill and Other Intangible Assets (Details 2) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Definite-lived intangible assets
Carrying amount of indefinite-lived intangible assets	$ 645	$ 644
Carrying amount of indefinite-lived intangible assets	67	67
Amount of indefinite-lived intangible assets acquired	5
Gross Carrying Amount	498	531
Accumulated Amortization	(390)	(398)
Net Carrying Amount	108	133
Definite-lived intangible assets acquired during the year, amount assigned	$ 10
Definite-lived intangible assets acquired during the year, weighted-average amortization period	5 years
Aggregate amortization expense for definite-lived intangible assets	$ 28	33	$ 40
Estimated intangible amortization expense for next five years:
2017	24
2018	22
2019	20
2020	14
2021	12
Customer relationships [Member]
Definite-lived intangible assets
Gross Carrying Amount	144	149
Accumulated Amortization	(112)	(106)
Net Carrying Amount	32	43
Contracts [Member]
Definite-lived intangible assets
Gross Carrying Amount	213	233
Accumulated Amortization	(177)	(189)
Net Carrying Amount	36	44
Other [Member]
Definite-lived intangible assets
Gross Carrying Amount	141	149
Accumulated Amortization	(101)	(103)
Net Carrying Amount	$ 40	$ 46