Derivatives and Hedging Activities (Details 4) (USD $)			9 Months Ended
	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2013 July 1, 2013 to December 31, 2013		Sep. 30, 2013 2014	Sep. 30, 2013 2015	Sep. 30, 2013 2016	Sep. 30, 2013 2017	Sep. 30, 2013 2018-2027
Summary of Option Premiums Payable and Receivable
Premiums Payable			$ 104,000,000	[1]	$ 347,000,000	$ 320,000,000	$ 289,000,000	$ 238,000,000	$ 783,000,000
Premiums Receivable			20,000,000	[1]	58,000,000	65,000,000	49,000,000	44,000,000	107,000,000
Gross notional amount of index options and futures contracts	1,500,000,000	1,300,000,000
Gross notional amount of forwards, futures, total return swaps and commodity swaps	128,000,000	146,000,000
Gross notional amount of foreign currency forward contracts	34,000,000	14,000,000
Gross notional amount of futures contracts	$ 35,000,000	$ 5,000,000

[1] 2013 amounts represent the amounts payable and receivable for the period from October 1, 2013 to December 31, 2013.