Fair Values (Details) (USD $)	Sep. 30, 2013	Dec. 31, 2012
Investment securities:
Equity securities	$ 168,000,000	$ 296,000,000
Debt securities and other	4,969,000,000	5,318,000,000
Derivatives	662,000,000	942,000,000
Total assets	5,799,000,000	6,556,000,000
Level 1 [Member]
Investment securities:
Equity securities	168,000,000	296,000,000
Debt securities and other	232,000,000	338,000,000
Derivatives	0	0
Total assets	400,000,000	634,000,000
Level 2 [Member]
Investment securities:
Equity securities	0	0
Debt securities and other	4,737,000,000	4,980,000,000
Derivatives	662,000,000	942,000,000
Total assets	5,399,000,000	5,922,000,000
Level 3 [Member]
Investment securities:
Total assets	$ 0	$ 0