Investments and Derivative Instruments (Details Textual 3) (USD $)	3 Months Ended
	Mar. 31, 2013 securities	Mar. 31, 2012	Dec. 31, 2012
Net realized capital gains (losses), excluding net OTTI losses recognized in earnings	$ 42,000,000	$ (881,000,000)
Document Period End Date	Mar. 31, 2013
Percent of fair value of securities transferred for collateral obtained on repurchase agreement	at least 95%
Additional Investments and Derivative Instruments (Textual) [Abstract]
Gross gains and losses on sales and impairments previously reported as unrealized losses in AOCI	1,600,000,000	133,000,000
Proceeds from sales of AFS securities	8,700,000,000	12,700,000,000
Number of securities included in AFS securities in an unrealized loss position, primarily related to municipal securities	1,967
Percentage of gross unrealized losses depressed	90.00%
Securities Depressed to Cost or Amortized Cost Lower Limit	20.00%
Number of years to maturity for securities concentrated in the financial services sector	10 years
Carrying value of mortgage loans associated with the valuation allowance	307,000,000		291,000,000
Valuation allowances on mortgage loans held for sale	3,000,000		3,000,000
Mortgage loans held for sale, carrying value	47,000,000		47,000,000
Current weighted average loan to value ratio of commercial mortgage loan	58.00%
Original weighted average loan to value ratio of commercial mortgage loan	63.00%
Avg. Debt-Service Coverage Ratio	2.08
Securities sold under agreements to repurchase	2,500,000,000
Notional amount of interest rate swaps in offsetting relationships			7,500,000,000
Deferred net gains on derivative instruments before tax to be reclassified to earnings during next twelve months	91,000,000
Maximum Term Over for Hedging Exposure to Variability of Future Cash Flows	3 years
Derivative fair value reported as liabilities	1,400,000,000		1,500,000,000
Increase in notional amount of hedging instruments	11,400,000,000
Maximum amount of net reclassifications from AOCI to earnings		0
Policyholder Behavior Assumptions [Member]
Derivative, Gain (Loss) on Derivative, Net	1,000,000	0
International Program Hedging Instruments [Member]
Notional Amount	72,123,000,000		63,085,000,000
Retirement Plans and Individual Life Businesses [Member]
Net realized capital gains (losses), excluding net OTTI losses recognized in earnings	1,500,000,000
Gain (Loss) on Derivative Instruments, Net, Pretax	$ 100,000,000