Equity Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Equity [Abstract]
Net unrealized gains on available-for-sale securities for which we have not recorded OTTI, net of tax	$ 135	$ 455	$ 592
Net unrealized gains on available-for-sale securities for which we have recorded OTTI, net of tax	581	903	1,529
Prior service credit (cost) and actuarial gains (losses), net of amortization, and other, net of tax	43	49	(388)
Accumulated other comprehensive income	$ 759	$ 1,407	$ 1,733