Equity Changes in AOCI (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	$ 3,680
Total other comprehensive income (loss)	(326)	$ 530	$ 819
Ending balance	4,030	3,680
Accumulated Net Unrealized Investment Gain (Loss) [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	2,121	1,627
Other comprehensive income before reclassifications	(280)	722
Amounts reclassified from other comprehensive income	(483)	(228)
Total other comprehensive income (loss)	(763)	494
Ending balance	1,358	2,121	1,627
Accumulated Other Comprehensive Income (Loss), Other [Member]
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	(388)	(424)
Other comprehensive income before reclassifications	17	37
Amounts reclassified from other comprehensive income	420	(1)
Total other comprehensive income (loss)	437	36
Ending balance	49	(388)	(424)
Accumulated Other Comprehensive Income (Loss)
Increase (Decrease) in Accumulated Other Comprehensive Income [Roll Forward]
Beginning Balance	1,733	1,203
Other comprehensive income before reclassifications	(263)	759
Amounts reclassified from other comprehensive income	(63)	(229)
Total other comprehensive income (loss)	(326)	530
Ending balance	$ 1,407	$ 1,733	$ 1,203