Fair Values (Details) (USD $) In Millions, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Investment securities:
Equity securities	$ 68	$ 124
Debt securities and other	4,693	4,892
Derivatives	600	701
Total assets	5,361	5,717
Level 1 [Member]
Investment securities:
Equity securities	68	124
Debt securities and other	271	320
Derivatives	0	0
Total assets	339	444
Level 2 [Member]
Investment securities:
Equity securities	0	0
Debt securities and other	4,422	4,572
Derivatives	600	701
Total assets	5,022	5,273
Level 3 [Member]
Investment securities:
Equity securities	0	0
Debt securities and other	0	0
Derivatives	0	0
Total assets	$ 0	$ 0