Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Debt Instrument [Line Items]
Non-cash modifications of certain mortgage loans, fixed income securities, limited partnerships and other investments, as well as mergers completed with equity securities	$ 96	$ 102	$ 306
Payments of Dividends	103
Liabilities for collateral received reported in other liabilities and accrued expenses	539	508	322
Obligations to return cash collateral for over-the-counter ("OTC") derivatives reported in other liabilities and accrued expenses or other investments	11	2	6
Net change in proceeds managed
Net change in short-term investments	(41)	(182)	235
Operating cash flow (used) provided	(41)	(182)	235
Net change in cash	1	0	(2)
Net change in proceeds managed	(40)	(182)	233
Net change in liabilities
Liabilities for collateral, beginning of year	(510)	(328)	(561)
Liabilities for collateral, end of year	(550)	(510)	(328)
Operating cash flow provided (used)	40	$ 182	$ (233)
Limited Partnership [Member]
Debt Instrument [Line Items]
Liabilities Assumed	44
Debt and Equity Securities [Member]
Debt Instrument [Line Items]
Payments of Dividends	$ 86