Variable Interest Entities - Summary of Assets and Liabilities Related to Consolidated Variable Interest Entities (Details) (USD $)	Sep. 30, 2013		Dec. 31, 2012		Sep. 30, 2012
Variable Interest Entity [Line Items]
Interest bearing deposits with banks	$ 29,917,000,000		$ 13,279,000,000
Securities held-to-maturity	1,433,000,000		1,620,000,000
Other assets	8,585,000,000		7,069,000,000
Total assets	187,375,000,000	[1]	191,446,000,000	[1]	198,583,000,000
Other	4,357,000,000		4,562,000,000
Long-term debt	22,151,000,000		21,745,000,000
Total liabilities	169,993,000,000	[1]	173,610,000,000	[1]
Variable interest entities
Variable Interest Entity [Line Items]
Interest bearing deposits with banks	5,000,000		0
Securities held-to-maturity	208,000,000		0
Other assets	479,000,000		533,000,000
Total assets	692,000,000		533,000,000
Other	99,000,000		152,000,000
Long-term debt	92,000,000		92,000,000
Total liabilities	191,000,000		244,000,000
Asset-backed commercial paper conduits [Member]
Variable Interest Entity [Line Items]
Interest bearing deposits with banks	5,000,000		0
Securities held-to-maturity	208,000,000		0
Other assets	2,000,000		0
Total assets	215,000,000		0
Other	3,000,000		0
Total liabilities	3,000,000		0
Low Income Housing Limited Liability Partnership [Member]
Variable Interest Entity [Line Items]
Other assets	477,000,000		533,000,000
Total assets	477,000,000		533,000,000
Other	96,000,000		152,000,000
Long-term debt	92,000,000		92,000,000
Total liabilities	$ 188,000,000		$ 244,000,000

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities (“VIEs”) as of September 30, 2013 and December 31, 2012 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. September 30, December 31, 2013 2012 (in millions)Assets Interest bearing deposits with banks$5 $—Securities held-to-maturity208 —Other assets479 533Total assets$692 $533Liabilities Long-term debt92 92Interest, taxes and other liabilities99 152Total liabilities$191 $244