Investments and Derivative Instruments (Details 12) (USD $) In Millions, unless otherwise specified	Sep. 30, 2012	Dec. 31, 2011
GMWB reinsurance contracts
Notional Amount	$ 213,672	$ 196,608
Fair Value	(1,332)	(1,044)
UNITED STATES | GMWB hedging instruments [Member]
GMWB reinsurance contracts
Notional Amount	19,813	16,406
Fair Value	674	894
UNITED STATES | Macro Hedge Program [Member]
GMWB reinsurance contracts
Notional Amount	5,583	6,819
Fair Value	82	357
UNITED STATES | Macro Hedge Program [Member] | Equity Futures [Member]
GMWB reinsurance contracts
Notional Amount	0	59
Fair Value	0	0
UNITED STATES | Macro Hedge Program [Member] | Equity Options [Member]
GMWB reinsurance contracts
Notional Amount	5,583	6,760
Fair Value	82	357
UNITED STATES | Customized swaps [Member] | GMWB hedging instruments [Member]
GMWB reinsurance contracts
Notional Amount	8,153	8,389
Fair Value	269	385
UNITED STATES | Equity swaps, options and futures [Member] | GMWB hedging instruments [Member]
GMWB reinsurance contracts
Notional Amount	6,330	5,320
Fair Value	308	498
UNITED STATES | Interest rate swaps and futures [Member] | GMWB hedging instruments [Member]
GMWB reinsurance contracts
Notional Amount	5,330	2,697
Fair Value	$ 97	$ 11