Insurance (Details 6) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Fixed and Floating Rate Funding Agreements by Type [Line Items]
Outstanding funding agreements to certain SPEs	$ 30,000	$ 25,500
Funding agreements - Federal Agricultural Mortgage Corporation [Member]
Fixed and Floating Rate Funding Agreements by Type [Line Items]
Outstanding funding agreements to certain SPEs	2,750	2,750
Invested assets pledged as collateral	3,159	3,157
Federal Home Loan Bank Of New York [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank amount of advances by branch for funding agreements	13,512	11,655
Collateral pledged relating to obligations under funding agreements	14,611	13,002
Federal Home Loan Bank of Boston [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank amount of advances by branch for funding agreements	450	450
Collateral pledged relating to obligations under funding agreements	537	518
Federal Home Loan Bank of Des Moines [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank amount of advances by branch for funding agreements	1,405	695
Collateral pledged relating to obligations under funding agreements	1,902	953
Federal Home Loan Bank of Pittsburgh [Member]
Federal Home Loan Bank, Advances, Branch of FHLB Bank [Line Items]
Federal Home Loan Bank amount of advances by branch for funding agreements	0
Collateral pledged relating to obligations under funding agreements	$ 810