Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012
Held-to-maturity securities, fair value	$ 4,730	$ 3,992	$ 4,212
Unearned income on loans	827	957	980
Consolidated guaranteed funds VIEs, for accrued income and other assets	24	24	24
Consolidated education loan securitizations trust VIEs at fair value, Discontinued assets	2,158	2,158	2,158
Loan securitization trust VIEs	148	148	148
Aggregate amount of certificates of deposit	$100,000 or more	$100,000 or more	$100,000 or more
Consolidated education loan securitization trust VIEs at fair value, Discontinued liabilities	$ 2,037	$ 2,037	$ 2,037
Preferred stock, par value	$ 1	$ 1	$ 1
Preferred stock, shares authorized	25,000,000	25,000,000	25,000,000
Common shares, par value	$ 1	$ 1	$ 1
Common shares, shares authorized	1,400,000,000	1,400,000,000	1,400,000,000
Common shares, shares issued	1,016,969,905	1,016,969,905	1,016,969,905
Treasury stock, shares	119,148,654	91,201,285	80,775,030
Series A Preferred Stock [Member]
Preferred stock, liquidation preference	$ 100	$ 100	$ 100
Preferred stock, shares authorized	7,475,000	7,475,000	7,475,000
Preferred stock, shares issued, Total	2,904,839	2,904,839	2,904,839
Preferred stock, dividend rate	7.75%	7.75%	7.75%