Goodwill and Other Intangible Assets (Other Intangible Assets Narrative) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Finite-lived intangible assets acquired during the year	$ 10,000,000
Finite-Lived Intangible Assets, Gross	41,000,000	$ 82,000,000
Finite-Lived Intangible Assets, Net	14,000,000	31,000,000
Indefinite-Lived Intangible Assets (Excluding Goodwill)	86,000,000	121,000,000
Capitalized Computer Software, Gross	1,300,000,000	1,500,000,000
Capitalized Computer Software, Net	574,000,000	771,000,000
Capitalized Computer Software, Development Stage Costs	33,000,000
Impairment of Long-Lived Assets Held-for-use	$ 1,919,000,000	68,000,000	$ 41,000,000
Amortization of software to be abandoned			75,000,000
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
Amortization expense	14,000,000	15,000,000	13,000,000
Amortization expense for 2017	4,000,000
Amortization expense for 2018	3,000,000
Amortization expense for 2019	1,000,000
Amortization expense for 2020	1,000,000
Amortization expense for 2021	1,000,000
Amortization expense thereafter	4,000,000
Capitalized Internal Use Software [Member]
Finite-Lived Intangible Assets [Line Items]
Acquired Finite-lived Intangible Asset, Residual Value	0
Amortization expense	201,000,000	$ 212,000,000	260,000,000
Amortization expense for 2017	176,000,000
Amortization expense for 2018	125,000,000
Amortization expense for 2019	83,000,000
Amortization expense for 2020	60,000,000
Amortization expense for 2021	48,000,000
Amortization expense thereafter	$ 82,000,000
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
Software In-Process [Member]
Finite-Lived Intangible Assets [Line Items]
Impairment of Long-Lived Assets Held-for-use			$ 24,000,000
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