Deferred Policy Acquisition Costs, Value of Business Acquired and Other Policy-Related Intangibles (DAC and VOBA) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Beginning Balance of DAC	$ 5,015	$ 5,667	$ 5,066
Capitalizations of DAC	319	256	330
Net investment gains (losses) of DAC and net derivative gains (losses) of DAC	(370)	127	1,371
Other expenses of DAC	(535)	(958)	(1,076)
Total amortization of DAC	(905)	(831)	295
Unrealized investment gains (losses) of DAC	89	(77)	(24)
Ending Balance of DAC	4,518	5,015	5,667
Beginning Balance of VOBA	608	672	711
Net investment gains (losses) of VOBA and net derivative gains (losses) of VOBA	(1)	(9)	2
Other expenses of VOBA	(105)	(76)	(72)
Total amortization of VOBA	(106)	(85)	(70)
Unrealized investment gains (losses) of VOBA	66	21	31
Ending Balance of VOBA	568	608	672
Balance at December 31,	$ 5,086	$ 5,623	$ 6,339