Derivatives Derivatives (NQ, CF, FV) (Details) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Derivative [Line Items]
Gain (Loss) on Discontinuation of Cash Flow Hedge Due to Forecasted Transaction Probable of Not Occurring, Net	$ 0	$ 0	$ 0	$ 12
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(7)	(52)	28	(104)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(1)	3	8	(42)
Cash Flow Hedging
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(7)	(52)	28	(104)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	(10)
Cash Flow Hedging | Interest rate contracts
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(3)	1	(5)	3
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Cash Flow Hedging | Foreign currency exchange rate contracts
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(4)	(53)	33	(107)
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	(10)
Fair Value Hedging
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	2	(1)	12	(2)
Fair Value Hedging | Interest rate contracts
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	2	(1)	12	(2)
Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	1	4	3
Net investment income | Cash Flow Hedging
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	1	4	4
Net investment income | Cash Flow Hedging | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	1	4	4
Net investment income | Cash Flow Hedging | Foreign currency exchange rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Net investment income | Fair Value Hedging
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Net investment income | Fair Value Hedging | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Net derivative gains (losses)
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(723)	(234)	(1,469)	(1,418)
Net derivative gains (losses) | Cash Flow Hedging
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	46	0	61	13
Net derivative gains (losses) | Cash Flow Hedging | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	46	0	62	2
Net derivative gains (losses) | Cash Flow Hedging | Foreign currency exchange rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	(1)	11
Net derivative gains (losses) | Fair Value Hedging
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	1	(12)	2
Net derivative gains (losses) | Fair Value Hedging | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	1	(12)	2
Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	(79)	(4)	(355)
Policyholder benefits and claims | Cash Flow Hedging
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder benefits and claims | Cash Flow Hedging | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder benefits and claims | Cash Flow Hedging | Foreign currency exchange rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder benefits and claims | Fair Value Hedging
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder benefits and claims | Fair Value Hedging | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Not Designated as Hedging Instrument
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(3)	4	(4)	(30)
Not Designated as Hedging Instrument | Interest rate contracts
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Not Designated as Hedging Instrument | Foreign currency exchange rate contracts
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(3)	4	(4)	(30)
Not Designated as Hedging Instrument | Credit
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Not Designated as Hedging Instrument | Equity market contracts
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0		0	0
Not Designated as Hedging Instrument | Embedded Derivative Financial Instruments
Derivative [Line Items]
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Not Designated as Hedging Instrument | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	(1)
Not Designated as Hedging Instrument | Net investment income | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Not Designated as Hedging Instrument | Net investment income | Foreign currency exchange rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Not Designated as Hedging Instrument | Net investment income | Credit
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Not Designated as Hedging Instrument | Net investment income | Equity market contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	(1)
Not Designated as Hedging Instrument | Net investment income | Embedded Derivative Financial Instruments
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Not Designated as Hedging Instrument | Net derivative gains (losses)
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(767)	(235)	(1,518)	(1,433)
Not Designated as Hedging Instrument | Net derivative gains (losses) | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(281)	(81)	(1,255)	(145)
Not Designated as Hedging Instrument | Net derivative gains (losses) | Foreign currency exchange rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	2	(30)	17	(72)
Not Designated as Hedging Instrument | Net derivative gains (losses) | Credit
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	8	6	(2)	17
Not Designated as Hedging Instrument | Net derivative gains (losses) | Equity market contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(458)	(712)	(942)	(2,123)
Not Designated as Hedging Instrument | Net derivative gains (losses) | Embedded Derivative Financial Instruments
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(38)	582	664	890
Not Designated as Hedging Instrument | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	(79)	(4)	(355)
Not Designated as Hedging Instrument | Policyholder benefits and claims | Interest rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	6	0	8
Not Designated as Hedging Instrument | Policyholder benefits and claims | Foreign currency exchange rate contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Not Designated as Hedging Instrument | Policyholder benefits and claims | Credit
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Not Designated as Hedging Instrument | Policyholder benefits and claims | Equity market contracts
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(64)	0	(341)
Not Designated as Hedging Instrument | Policyholder benefits and claims | Embedded Derivative Financial Instruments
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ (2)	$ (21)	$ (4)	$ (22)