Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Supplemental Cash Flow Information [Abstract]
Non-cash modifications of certain mortgage loans, fixed income securities, limited partnership interests and other investments, as well as mergers completed with equity securities	$ 131	$ 120	$ 322
Liabilities Assumed	89
Non-cash financing activities related to the issuance of shares for vested restricted stock units	74	47	94
Liabilities for collateral received reported in other liabilities and accrued expenses	829	780	609
Obligations to return cash collateral for over-the-counter ("OTC") and cleared derivatives reported in other liabilities and accrued expenses or other investments	11	2	15
Net change in proceeds managed
Net change in short-term investments	(59)	(167)	190
Operating cash flow (used) provided	(59)	(167)	190
Net change in cash	1	9	(6)
Net change in proceeds managed	(58)	(158)	184
Net change in liabilities
Liabilities for collateral, beginning of year	(782)	(624)	(808)
Liabilities for collateral, end of year	(840)	(782)	(624)
Operating cash flow provided (used)	$ 58	$ 158	$ (184)