Derivatives (Gains Losses Recognized in Income Not Designated or Qualifying) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (55)	$ (297)	$ 57
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net derivative gains (losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(5,268)	(766)	576
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net derivative gains (losses) | Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(3,862)	(421)	1,545
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net derivative gains (losses) | Foreign currency exchange rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	958	547	(344)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net derivative gains (losses) | Credit derivatives — purchased
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(40)	7	(12)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net derivative gains (losses) | Credit derivatives — written
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	81	(83)	21
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net derivative gains (losses) | Equity derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2,405)	(816)	(634)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net Investment Income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(22)	(17)	(18)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net Investment Income | Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net Investment Income | Foreign currency exchange rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net Investment Income | Credit derivatives — purchased
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(3)	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net Investment Income | Credit derivatives — written
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Net Investment Income | Equity derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(22)	(14)	(18)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Policyholder benefits and claims
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(434)	(20)	(246)
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Policyholder benefits and claims | Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	42	5	42
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Policyholder benefits and claims | Foreign currency exchange rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(18)	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Policyholder benefits and claims | Credit derivatives — purchased
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Policyholder benefits and claims | Credit derivatives — written
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments [Member] | Policyholder benefits and claims | Equity derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (458)	$ (25)	$ (288)