Goodwill and Other Intangible Assets - Gross Carrying Amount, Accumulated Amortization And Net Carrying Amount Of Other Intangible Assets (Details) - USD ($) $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	$ 3,312	$ 3,300
Accumulated Amortization	(1,630)	(1,532)
Net Carrying Amount	1,682	1,768	$ 1,871	$ 2,025
Client relationships
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	2,490	2,486
Accumulated Amortization	(1,268)	(1,198)
Net Carrying Amount	1,222	1,288
Core deposits
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	671	667
Accumulated Amortization	(265)	(246)
Net Carrying Amount	406	421
Other
Finite-Lived Intangible Assets [Line Items]
Gross Carrying Amount	151	147
Accumulated Amortization	(97)	(88)
Net Carrying Amount	$ 54	$ 59