Reinsurance (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Ceded Credit Risk [Line Items]
Maximum retention per single insured life on fixed and VUL insurance contracts	$ 20
Percent of mortality risk reinsured on newly issued non-term life insurance contracts	25.00%
Percent of total individual life in-force amount reinsured	41
Reserves associated with modified coinsurance reinsurance arrangements	$ 571
Reinsurance receivable	5,300	$ 5,600
Policy loans	2,451	2,545
Liabilities for funds withheld	1,976	638
Proceeds From Reinsurance Recapture			$ 422
Realized Gain Loss	(339)	(151)
Current Period Increase In Reserves	360
Swiss Re [Member]
Ceded Credit Risk [Line Items]
Reinsurance receivable	2,100	2,400
Trust funded by Swiss Re to support reinsurance receivable	2,600
Liabilities for funds withheld	495
Liabilities for reinsurance related embedded derivatives	$ 47
Amortization period (in years) of deferred gain on business sold to Swiss Re	15 years
Amount of amortization, after-tax, of deferred gain on business sold to Swiss Re	$ 48	$ 48	$ 48
Reinsurance Recaptured [Member]
Ceded Credit Risk [Line Items]
Proceeds From Reinsurance Recapture	500
Reimbursement for prepaid reinsurance premiums	78
Realized Gain Loss	57
Current Period Increase In Reserves	226
Reduction of DAC	$ (123)