Statutory Financial Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Statutory Accounting Practices [Line Items]
Approximate increase in statutory capital and surplus resulting from discount of certain A&E liabilities	$ 161	$ 192
U.S. Subsidiairies
Statutory Accounting Practices [Line Items]
Dividends available to be paid	762
Statutory capital and surplus	6,037	5,858
Statutory net income	619	702	1,025
Other International Subsidiaries
Statutory Accounting Practices [Line Items]
Dividends available to be paid	2,100
Statutory capital and surplus	18,317	15,565
Statutory net income	$ 2,118	$ 1,214	$ 2,592