Derivatives and Hedging Activities (Details 2) (USD $) In Millions, unless otherwise specified	Mar. 31, 2013	Dec. 31, 2012
Derivatives and Hedging Activities
Asset	$ 3,150	$ 3,418
Derivatives not designated as hedging instruments
Derivatives and Hedging Activities
Asset	3,150	3,418
Liability	3,661	4,159
Derivatives not designated as hedging instruments | GMWB and GMAB
Derivatives and Hedging Activities
Asset	3,136	3,412
Liability	3,592	4,111
Derivatives not designated as hedging instruments | GMWB and GMAB | Interest rate contracts
Derivatives and Hedging Activities
Asset	1,937	2,191
Liability	1,421	1,486
Derivatives not designated as hedging instruments | GMWB and GMAB | Equity contracts
Derivatives and Hedging Activities
Asset	1,192	1,215
Liability	1,904	1,792
Derivatives not designated as hedging instruments | GMWB and GMAB | Foreign currency contracts
Derivatives and Hedging Activities
Asset	7	6
Liability	1
Derivatives not designated as hedging instruments | GMWB and GMAB | Embedded derivatives
Derivatives and Hedging Activities
Liability	266	833
Derivatives not designated as hedging instruments | EIA embedded derivatives | Equity contracts
Derivatives and Hedging Activities
Liability	3	2
Derivatives not designated as hedging instruments | IUL | Equity contracts
Derivatives and Hedging Activities
Asset	14	6
Liability	5	1
Derivatives not designated as hedging instruments | IUL embedded derivatives | Equity contracts
Derivatives and Hedging Activities
Liability	61	45
Derivatives not designated as hedging instruments | Other derivatives
Derivatives and Hedging Activities
Asset	14	6
Liability	$ 69	$ 48