Investments and Derivative Instruments (Details Textuals 1) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Derivative [Line Items]
Net notional amount of investment hedge instruments	$ 1,700,000,000		$ 1,700,000,000		$ 1,700,000,000
Notional Amount	126,446,000,000		126,446,000,000		136,854,000,000
Japanese variable annuity hedging [Member] | Long foreign currency forwards [Member]
Derivative [Line Items]
Notional Amount	2,600,000,000		2,600,000,000		1,700,000,000
Japanese variable annuity hedging [Member] | Short foreign currency forwards [Member]
Derivative [Line Items]
Notional Amount	937,000,000		937,000,000
Macro hedge program [Member]
Derivative [Line Items]
Net notional amount of investment hedge instruments	7,900,000,000		7,900,000,000		16,600,000,000
Notional Amount	18,673,000,000		18,673,000,000		26,210,000,000
Long foreign currency forwards [Member] | Macro hedge program [Member]
Derivative [Line Items]
Notional Amount	13,300,000,000		13,300,000,000		21,400,000,000
Short foreign currency forwards [Member] | Macro hedge program [Member]
Derivative [Line Items]
Notional Amount	5,400,000,000		5,400,000,000		4,800,000,000
Contingent capital facility put option [Member]
Derivative [Line Items]
Maximum aggregate principal amount of junior subordinated notes	500,000,000		500,000,000
Notional Amount	500,000,000		500,000,000		500,000,000
Japan 3 Win Related Foreign Currency Swaps [Member]
Derivative [Line Items]
Associated liability adjusted for changes in spot rates through realized capital gain	(49,000,000)	(103,000,000)	(7,000,000)	(96,000,000)
Notional Amount	2,285,000,000		2,285,000,000		2,285,000,000
Japanese fixed annuity hedging instruments [Member]
Derivative [Line Items]
Associated liability adjusted for changes in spot rates through realized capital gain	(63,000,000)	(126,000,000)	(10,000,000)	(119,000,000)
Notional Amount	$ 2,137,000,000		$ 2,137,000,000		$ 2,119,000,000