Investments and Derivative Instruments (Details 12) (USD $) In Millions, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
GMWB reinsurance contracts
Notional Amount	$ 151,155	$ 141,436
Fair Value	(1,045)	(458)
GMWB hedging instruments [Member]
GMWB reinsurance contracts
Notional Amount	19,289	16,406
Fair Value	525	894
Customized swaps [Member] | GMWB hedging instruments [Member]
GMWB reinsurance contracts
Notional Amount	8,760	8,389
Fair Value	239	385
Equity swaps, options and futures [Member] | GMWB hedging instruments [Member]
GMWB reinsurance contracts
Notional Amount	5,695	5,320
Fair Value	329	498
Interest rate swaps and futures [Member] | GMWB hedging instruments [Member]
GMWB reinsurance contracts
Notional Amount	4,834	2,697
Fair Value	$ (43)	$ 11