New Accounting Standards (Details) (USD $)	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Stockholders' Equity
Retained earnings	$ 0	$ 0	$ 31,000,000
Cumulative effect adjustment [Abstract]
Net cumulative effect adjustment	0	0	31,000,000
Unrealized OTTI on AFS Securities
Stockholders' Equity
Retained earnings	0	0	(18,000,000)
Cumulative effect adjustment [Abstract]
Net cumulative effect adjustment	0	0	(18,000,000)
Unrealized Gain (Loss) on AFS Securities
Stockholders' Equity
Retained earnings	0	181,000,000	(84,000,000)
Cumulative effect adjustment [Abstract]
Net cumulative effect adjustment	0	181,000,000	(84,000,000)
Consolidation of Variable Interest Entities [Member]
Stockholders' Equity
Retained earnings			169,000,000
Cumulative effect adjustment [Abstract]
Net cumulative effect adjustment			169,000,000
Amendments to Investments - Debt and Equity Securities Topic [Member]
Stockholders' Equity
Retained earnings			102,000,000
Cumulative effect adjustment [Abstract]
Impact of adoption on basic earnings per share amounts (in dollars per share)			$ 0.98
Impact of adoption on diluted per share amounts (in dollars per share)			$ 0.98
Net cumulative effect adjustment			102,000,000
Accounting for costs associated with acquiring or renewing insurance contracts [Member]
Cumulative effect adjustment [Abstract]
Cumulative effect from adoption of new accounting standard lower bound	950,000,000
Cumulative effect from adoption of new accounting standard higher bound	$ 1,150,000,000