Fair Values (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Investment securities:
Equity securities	$ 24.0	$ 124.0
Debt securities and other	4,831	4,892
Derivatives	502	701
Total assets	5,357	5,717
Level 1 [Member]
Investment securities:
Equity securities	24.0	124.0
Debt securities and other	350	320
Derivatives	0	0
Total assets	374	444
Level 2 [Member]
Investment securities:
Equity securities	0	0
Debt securities and other	4,481	4,572
Derivatives	502	701
Total assets	4,983	5,273
Level 3 [Member]
Investment securities:
Equity securities	0	0
Debt securities and other	0	0
Derivatives	0	0
Total assets	$ 0	$ 0