Deferred Policy Acquisition Costs, Value of Business Acquired and Other Policy-Related Intangibles (Negative VOBA) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Finite Lived Intangible Liabilities
Balance at January 1,	$ 935	$ 1,193	$ 1,596
Amortization of negative VOBA	(140)	(269)	(361)
Effect of foreign currency translation and other	32	11	(42)
Balance at December 31,	827	935	1,193
Accumulated amortization	$ 3,174	$ 3,034	$ 2,765