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, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net [Abstract]
Beginning Balance of DAC	$ 13,830	$ 13,464	$ 13,024
Capitalization of DAC	3,002	3,152	3,319
Net investment gains (losses) of DAC and net derivative gains (losses) of DAC	60	229	(150)
Other expenses of DAC	(2,426)	(2,555)	(2,590)
Total amortization of DAC	(2,366)	(2,326)	(2,740)
Unrealized investment gains (losses) of DAC	(525)	(171)	443
Effect of foreign currency translation and other of DAC	848	(289)	(582)
Ending Balance of DAC	14,789	13,830	13,464
Beginning Balance of VOBA	3,760	3,966	4,705
Net investment gains (losses) of VOBA and net derivative gains (losses) of VOBA	0	(3)	(1)
Other expenses of VOBA	(315)	(389)	(443)
Total amortization of VOBA	(315)	(392)	(444)
Unrealized investment gains (losses) of VOBA	(4)	8	5
Effect of foreign currency translation and other of VOBA	189	178	(300)
Ending Balance of VOBA	3,630	3,760	3,966
Balance at December 31,	$ 18,419	$ 17,590	$ 17,430