Investments and Derivative Instruments (Details Textual 3) (USD $)	3 Months Ended		9 Months Ended
	Mar. 31, 2013 Security	Mar. 31, 2012	Sep. 30, 2011	Dec. 31, 2012
Invested Assets Suppoting Modco	$ 1,300,000,000
Gain (Loss) on Investments, Excluding Other than Temporary Impairments	(113,000,000)	(1,212,000,000)
Derivative Liability, Fair Value, Amount Offset Against Collateral	(10,000,000)			(54,000,000)
Financial Instruments, Owned and Pledged as Collateral, at Fair Value	904,000,000			923,000,000
Additional Investments and Derivative Instruments (Textual) [Abstract]
Gross gains and losses on sales and impairments previously reported as unrealized losses in AOCI	2,000,000		77,000,000
Proceeds from sales of AFS securities	4,800,000,000	8,500,000,000
Number of securities included in AFS securities in an unrealized loss position, primarily related to municipal securities	1,224
Percentage of gross unrealized losses depressed	88.00%
Securities Depressed to Cost or Amortized Cost Lower Limit	20.00%
Minimum maturity of securities included in continuous loss position	10 years
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	164,000,000
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	56.00%
Original weighted average loan to value ratio of commercial mortgage loan	63.00%
Avg. Debt-Service Coverage Ratio	2.13
Collateral received as percentage of fair value of securities loaned	95.00%
Percent of fair value of securities transferred for collateral obtained on repurchase agreement	at least 95%
Securities transferred fair value	1,300,000,000			1,600,000,000
Notional amount of interest rate swaps in offsetting relationships				5,100,000,000
Deferred net gains on derivative instruments before tax to be reclassified to earnings during next twelve months	53,000,000
Increase in notional amount of hedging instruments	6,700,000,000
Maximum amount of net reclassifications from AOCI to earnings			0
Retirement Plans and Individual Life Businesses [Member]
Gain (Loss) on Investments, Excluding Other than Temporary Impairments	1,500,000,000
Gain (Loss) on Derivative Instruments, Net, Pretax	100,000,000
Securities Loaned or Sold under Agreements to Repurchase [Member]
Derivative Liability, Fair Value, Amount Offset Against Collateral	$ 904,000,000			$ 923,000,000