Supplemental Cash Flow Information (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Supplemental Cash Flow Information
Non-cash modifications of certain mortgage loans , fixed income securities, limited partnerships and other investments, as well as mergers completed with equity securities	$ 203	$ 109
Non-cash financing activities related to the issuance of shares for vested restricted stock units	92	39
Net change in proceeds managed
Net change in short-term investments	113	(202)
Operating cash flow provided (used)	113	(202)
Net change in cash	3	(1)
Net change in proceeds managed	116	(203)
Net change in liabilities
Liabilities for collateral, beginning of year	(808)	(462)
Liabilities for collateral, end of period	(692)	(665)
Operating cash flow (used) provided	$ (116)	$ 203