Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Per Share data, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Held-to-maturity securities, fair value	$ 3,992	$ 2,133
Unearned income on loans	957	1,388
Consolidated guaranteed funds VIEs, for accrued income and other assets	50
Consolidated education loan securitizations trust VIEs at fair value, Discontinued assets	2,395
Aggregate amount of certificates of deposit	100,000 or more	100,000 or more
Consolidated education loan securitization trust VIEs at fair value, Discontinued liabilities	$ 2,181
Preferred stock, par value	$ 1	$ 1
Preferred stock, shares authorized	25,000,000	25,000,000
Common shares, par value	$ 1	$ 1
Common shares, shares authorized	1,400,000,000	1,400,000,000
Common shares, shares issued	1,016,969,905	1,016,969,905
Treasury stock, shares	91,201,285	63,962,113
Series A Preferred Stock [Member]
Preferred stock, liquidation preference	$ 100	$ 100
Preferred stock, shares authorized	7,475,000	7,475,000
Preferred stock, shares issued	2,904,839	2,904,839
Preferred stock, dividend rate	7.75%	7.75%