Investments (Held-To-Maturity Securities Continuous Unrealized Loss Position) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010
Less than 12 Months, Fair Value	$ 284
Less than 12 Months, Unrealized Losses	(31)
12 Months or Longer, Fair Value	2,185	3,760
12 Months or Longer, Unrealized Losses	(340)	(279)
Total, Fair Value	2,469	3,760
Total, Unrealized Losses	(371)	(279)
Variable Interest Entities [Member] | Other ABS [Member]
Less than 12 Months, Fair Value	284
Less than 12 Months, Unrealized Losses	(31)
12 Months or Longer, Fair Value	2,185	3,760
12 Months or Longer, Unrealized Losses	(340)	(279)
Total, Fair Value	2,469	3,760
Total, Unrealized Losses	$ (371)	$ (279)