Goodwill and Other Intangibles (Amortized Intangible Assets) (Details) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Finite-Lived Intangible Assets [Line Items]
Gross Cost	$ 1,486	$ 1,457
Accumulated Amortization	451	421
Net Carrying Amount	1,035	1,036
Other Intangible Assets
Finite-Lived Intangible Assets [Line Items]
Gross Cost	174	176
Accumulated Amortization	79	74
Net Carrying Amount	95	102
Customer Lists
Finite-Lived Intangible Assets [Line Items]
Gross Cost	1,312	1,281
Accumulated Amortization	372	347
Net Carrying Amount	$ 940	$ 934