Fair Value Measurements (Details Textual 1) (USD $)					3 Months Ended		6 Months Ended
	Jun. 30, 2013	Dec. 31, 2012	Jun. 30, 2013 Derivative Liabilities [Member]	Dec. 31, 2012 Derivative Liabilities [Member]	Jun. 30, 2013 US Treasury Securities [Member]	Jun. 30, 2012 US Treasury Securities [Member]	Jun. 30, 2013 US Treasury Securities [Member]	Jun. 30, 2012 US Treasury Securities [Member]
Debt Instrument [Line Items]
Transfer from Level 1 to Level 2					$ 76,000,000	$ 622,000,000	$ 154,000,000	$ 648,000,000
Fair Value Measurements - Financial Instruments Excluding Guaranteed Living Benefits (Textual) [Abstract]
Transfer of amount from level 2 to 1	0
Cash collateral liability			27,000,000	92,000,000
Investment sales receivable	$ 10,500,000,000	$ 3,100,000,000
Derivatives priced by valuation models	97.00%	98.00%