Consolidated Balance Sheets (Parenthetical) (USD $) In Millions, except Share data, unless otherwise specified	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2012
Held-to-maturity securities, fair value	$ 4,716	$ 3,992	$ 4,396
Unearned income on loans	901	957	1,155
Consolidated guaranteed funds VIEs, for accrued income and other assets	22
Consolidated education loan securitizations trust VIEs at fair value, Discontinued assets	2,341
Loan securitization trust VIEs	151
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	$ 2,139
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	104,086,859	91,201,285	71,496,550
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%