Goodwill and Other Intangible Assets (Other Intangible Assets Narrative) (Details) - USD ($)	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired during the year			$ 0
Finite-Lived Intangible Assets, Gross	$ 18,000,000		18,000,000		$ 41,000,000
Finite-Lived Intangible Assets, Net	11,000,000		11,000,000		14,000,000
Indefinite-Lived Intangible Assets (Excluding Goodwill)	80,000,000		80,000,000		86,000,000
Capitalized Computer Software, Gross	1,300,000,000		1,300,000,000		1,300,000,000
Capitalized Computer Software, Net	472,000,000		472,000,000		$ 574,000,000
Capitalized Computer Software, Development Stage Costs	29,000,000		29,000,000
Impairment of Long-Lived Assets Held-for-use			$ 363,000,000	$ 1,695,000,000
Finite-Lived Intangible Assets, Except Capitalized Internal-Use Software [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Weighted-Average Useful Life			6 years
Acquired Finite-lived Intangible Asset, Residual Value	0		$ 0
Amortization expense	1,000,000	$ 3,000,000	3,000,000	10,000,000
Amortization expense for remainder 2017	1,000,000		1,000,000
Amortization expense for 2018	3,000,000		3,000,000
Amortization expense for 2019	1,000,000		1,000,000
Amortization expense for 2020	1,000,000		1,000,000
Amortization expense for 2021	1,000,000		1,000,000
Amortization expense for 2022	1,000,000		1,000,000
Amortization expense thereafter	3,000,000		3,000,000
Capitalized Internal Use Software [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Asset, Residual Value	0		0
Amortization expense	46,000,000	$ 48,000,000	141,000,000	$ 153,000,000
Amortization expense for remainder 2017	41,000,000		41,000,000
Amortization expense for 2018	151,000,000		151,000,000
Amortization expense for 2019	93,000,000		93,000,000
Amortization expense for 2020	73,000,000		73,000,000
Amortization expense for 2021	50,000,000		50,000,000
Amortization expense for 2022	35,000,000		35,000,000
Amortization expense thereafter	$ 29,000,000		$ 29,000,000
Capitalized Internal Use Software, Except Significant System Conversions [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Weighted-Average Useful Life			3 years
Minimum [Member] | Capitalized Internal Use Software, Significant System Conversions [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Weighted-Average Useful Life			8 years
Maximum [Member] | Capitalized Internal Use Software, Significant System Conversions [Member]
Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Weighted-Average Useful Life			10 years