Derivatives (Gains Losses Recognized in Income Not Designated or Qualifying) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (9)	$ 501
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net derivative gains (losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1,579)	2,437
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net derivative gains (losses) | Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(659)	1,972
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net derivative gains (losses) | Foreign currency exchange rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	343	523
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net derivative gains (losses) | Credit derivatives — purchased
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(8)	(5)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net derivative gains (losses) | Credit derivatives — written
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	38	(6)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net derivative gains (losses) | Equity derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1,293)	(47)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net investment income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(1)	(10)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net investment income | Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	2	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net investment income | Foreign currency exchange rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net investment income | Credit derivatives — purchased
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	10
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net investment income | Credit derivatives — written
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(9)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Net investment income | Equity derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(3)	(11)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Policyholder benefits and claims
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(255)	73
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Policyholder benefits and claims | Interest rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	42
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Policyholder benefits and claims | Foreign currency exchange rate derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(1)
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Policyholder benefits and claims | Credit derivatives — purchased
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Policyholder benefits and claims | Credit derivatives — written
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0
Derivatives Not Designated or Not Qualifying as Hedging Instruments: | Policyholder benefits and claims | Equity derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (256)	$ 32