Related Party Transactions - Summary of Related Party Transactions (Details) (USD $)	Mar. 31, 2013		Dec. 31, 2012		Mar. 31, 2012
Assets:
Cash and due from banks	$ 1,238,000,000		$ 1,359,000,000
Interest bearing deposits with banks	17,059,000,000		13,279,000,000
Trading assets	34,658,000,000		35,995,000,000
Loans	62,932,000,000		63,258,000,000		53,869,000,000
Other assets	7,277,000,000		7,069,000,000
Total assets	193,010,000,000	[1]	196,567,000,000	[1]	191,332,000,000
Liabilities:
Deposits	117,049,000,000		117,671,000,000		137,527,000,000
Trading liabilities	19,488,000,000		19,820,000,000
Short-term borrowings	11,802,000,000		14,933,000,000
Long-term debt	22,039,000,000		21,745,000,000
Other	4,794,000,000		4,562,000,000
Total liabilities	175,172,000,000	[1]	178,731,000,000	[1]
Parent And Other Subsidiaries Of Common Parent [Member]
Assets:
Cash and due from banks	152,000,000		114,000,000
Interest bearing deposits with banks	672,000,000		714,000,000
Securities purchased under agreements to resell	180,000,000		0
Trading assets	19,625,000,000	[2]	21,370,000,000	[2]
Loans	4,779,000,000		4,514,000,000
Other assets	915,000,000		858,000,000
Total assets	26,323,000,000		27,570,000,000
Liabilities:
Deposits	19,830,000,000		13,863,000,000
Trading liabilities	22,940,000,000	[2]	23,910,000,000	[2]
Short-term borrowings	2,376,000,000		2,721,000,000
Long-term debt	3,990,000,000		3,990,000,000
Other	501,000,000		459,000,000
Total liabilities	$ 49,637,000,000		$ 44,943,000,000

[1] The following table summarizes assets and liabilities related to our consolidated variable interest entities (“VIEs”) as of December 31, 2012 and 2011 which are consolidated on our balance sheet. Assets and liabilities exclude intercompany balances that eliminate in consolidation. Assets: Interest bearing deposits with banks, $216 and $108, Other assets $533 and $520, Total assets $749 and $628 respectively. Liabilities: Long-term debt $92 and $55, Interest, taxes and other liabilities $152 and $166, Liabilities of discontinued operations $0 and $541, Total liabilities $244 and $762, respectively.

[2] Trading assets and liabilities exclude the impact of netting which allows the offsetting of amounts relating to certain contracts if certain conditions are met.