Purchased Loans (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Financing Receivable, Impaired [Line Items]
Provision for credit losses (benefit)	$ 273,000,000	$ 643,000,000	$ 987,000,000
Charge-offs	1,021,000,000	1,588,000,000	1,870,000,000
Specific allowance for loan and lease losses associated with purchased impaired loans	463,000,000	625,000,000
Purchased impaired loans	4,858,000,000	6,106,000,000	7,406,000,000
Purchased Impaired Loans [Member]
Financing Receivable, Impaired [Line Items]
Provision for credit losses (benefit)	(91,000,000)	11,000,000
Charge-offs	42,000,000	104,000,000
Specific allowance for loan and lease losses associated with purchased impaired loans	900,000,000	1,000,000,000
Net carrying value of the net accumulation of realized gains and losses on pooled loan recorded investments	0
Impaired Loans With Associated Allowance [Member]
Financing Receivable, Impaired [Line Items]
Purchased impaired loans	4,400,000,000
Impaired Loans Without Associated Allowance [Member]
Financing Receivable, Impaired [Line Items]
Purchased impaired loans	$ 500,000,000