Goodwill and Other Intangible Assets - Amortization Expense (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Amortization expense related to credit card relationships, core deposits and other intangible assets [Abstract]
Amortization expense	$ 380	$ 637	$ 957
Purchased credit card relationships
Amortization expense related to credit card relationships, core deposits and other intangible assets [Abstract]
Amortization expense	97	195	309
Other credit card-related intangibles
Amortization expense related to credit card relationships, core deposits and other intangible assets [Abstract]
Amortization expense	51	58	265
Core deposit intangibles
Amortization expense related to credit card relationships, core deposits and other intangible assets [Abstract]
Amortization expense	102	196	239
Other intangibles
Amortization expense related to credit card relationships, core deposits and other intangible assets [Abstract]
Amortization expense	$ 130	$ 188	$ 144