Derivatives Derivatives (NQ, CF, FV) (Details) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Derivative [Line Items]
Maximum Length of Time Hedged in Cash Flow Hedge			0 years		2 years
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	$ 0	$ 2	$ 8	$ (40)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(7)	(50)	28	(101)
Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	1	4	3
Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(699)	(231)	(1,362)	(1,277)
Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	(79)	(4)	(355)
Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(2)	3	(4)	(29)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Not Designated as Hedging Instrument [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	(1)
Not Designated as Hedging Instrument [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(742)	(232)	(1,411)	(1,288)
Not Designated as Hedging Instrument [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	(79)	(4)	(355)
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(281)	(81)	(1,255)	(145)
Interest Rate Contract [Member] | Not Designated as Hedging Instrument [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	6	0	8
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(2)	3	(4)	(29)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	2	(30)	17	(72)
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Credit Risk Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Credit Risk Contract [Member] | Not Designated as Hedging Instrument [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Credit Risk Contract [Member] | Not Designated as Hedging Instrument [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	8	5	(2)	16
Credit Risk Contract [Member] | Not Designated as Hedging Instrument [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Equity Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Equity Contract [Member] | Not Designated as Hedging Instrument [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	(1)
Equity Contract [Member] | Not Designated as Hedging Instrument [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(458)	(711)	(942)	(2,123)
Equity Contract [Member] | Not Designated as Hedging Instrument [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(64)	0	(341)
Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(13)	585	771	1,036
Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	(21)	(4)	(22)
Fair Value Hedging [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	2	(1)	12	(2)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Fair Value Hedging [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Fair Value Hedging [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	1	(12)	2
Fair Value Hedging [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Fair Value Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	2	(1)	12	(2)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0	0
Fair Value Hedging [Member] | Interest Rate Contract [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Fair Value Hedging [Member] | Interest Rate Contract [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(2)	1	(12)	2
Fair Value Hedging [Member] | Interest Rate Contract [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Cash Flow Hedging [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	(9)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(7)	(50)	28	(101)
Cash Flow Hedging [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	1	4	4
Cash Flow Hedging [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	45	0	61	9
Cash Flow Hedging [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Cash Flow Hedging [Member] | Interest Rate Contract [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(3)	0	(5)	1
Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	1	1	4	4
Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	45	0	62	0
Cash Flow Hedging [Member] | Interest Rate Contract [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Cash Flow Hedging [Member] | Foreign Exchange Contract [Member]
Derivative [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0	(9)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(4)	(50)	33	(102)
Cash Flow Hedging [Member] | Foreign Exchange Contract [Member] | Net investment income
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Cash Flow Hedging [Member] | Foreign Exchange Contract [Member] | Net Derivative Gain (Loss) [Member]
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	(1)	9
Cash Flow Hedging [Member] | Foreign Exchange Contract [Member] | Policyholder benefits and claims
Derivative [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 0	$ 0	$ 0	$ 0