Contracts Accounted for as Insurance - Gross Premium Receivable Net of Commissions on Assumed Business Roll Forward (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Gross Premium Receivable Net of Ceding Commissions [Roll Forward]
December 31,	$ 576	$ 693
Premiums receivable from acquisitions (see Note 2)	270	18
Gross written premiums on new business, net of commissions on assumed business	225	111
Gross premiums received, net of commissions on assumed business	(216)	(155)
Adjustments:
Changes in the expected term	0	(39)
Accretion of discount, net of commissions on assumed business	13	5
Foreign exchange translation	54	(25)
Subtotal	922	608
Other	0	0
September 30,	922	608
Variable Interest Entity, Primary Beneficiary [Member]
Adjustments:
September 30,	$ 10	$ 11