Investments and Cash - Roll Forward of Credit Losses in the Investment Portfolio (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Roll Forward of Credit Losses in the Investment Portfolio
Credit losses, beginning of period	$ 124	$ 80	$ 64
Additions for credit losses on securities for which an other-than-temporary-impairment was not previously recognized	3	64	18
Eliminations of securities issued by FG VIEs	0	(15)	0
Reductions for securities sold and other settlement during the period	(28)	(12)	(21)
Additions for credit losses on securities for which an other-than-temporary-impairment was previously recognized	9	7	19
Credit losses, end of period	$ 108	$ 124	$ 80