Derivatives Derivatives NQ, CF, FV (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	$ 3	$ (43)	$ (17)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	156	(152)	70
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(7)	(32)	(14)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0
Fair Value Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	12	(2)	(1)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0
Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(2)	(9)	(2)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	156	(152)	70
Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0
Net Derivative Gains (Losses)
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	576	(1,739)	(6,213)
Net Derivative Gains (Losses) | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	459	(1,749)	(6,252)
Net Derivative Gains (Losses) | Fair Value Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(12)	2	1
Net Derivative Gains (Losses) | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	129	8	38
Net Derivative Gains (Losses) | Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	579	1,237	(1,741)
Net investment income
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	5	5	(1)
Net investment income | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(1)	(6)
Net investment income | Fair Value Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Net investment income | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	5	6	5
Net investment income | Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Policyholder benefits and claims
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(8)	(349)	(328)
Policyholder benefits and claims | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(8)	(349)	(328)
Policyholder benefits and claims | Fair Value Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Policyholder benefits and claims | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Policyholder benefits and claims | Embedded Derivative Financial Instruments [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(8)	(16)	(4)
Interest rate contracts | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0
Interest rate contracts | Fair Value Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	12	(2)	(1)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0
Interest rate contracts | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(1)	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	(5)	1	28
Interest rate contracts | Net Derivative Gains (Losses) | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(736)	(325)	(2,873)
Interest rate contracts | Net Derivative Gains (Losses) | Fair Value Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(12)	2	1
Interest rate contracts | Net Derivative Gains (Losses) | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	129	0	35
Interest rate contracts | Net investment income | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Interest rate contracts | Net investment income | Fair Value Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Interest rate contracts | Net investment income | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	5	6	5
Interest rate contracts | Policyholder benefits and claims | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	8	(4)
Interest rate contracts | Policyholder benefits and claims | Fair Value Hedges
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Interest rate contracts | Policyholder benefits and claims | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Foreign Exchange Contract [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(7)	(32)	(14)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0
Foreign Exchange Contract [Member] | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	(1)	(9)	(2)
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	161	(153)	42
Foreign Exchange Contract [Member] | Net Derivative Gains (Losses) | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	65	(98)	76
Foreign Exchange Contract [Member] | Net Derivative Gains (Losses) | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	8	3
Foreign Exchange Contract [Member] | Net investment income | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Foreign Exchange Contract [Member] | Net investment income | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Foreign Exchange Contract [Member] | Policyholder benefits and claims | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Foreign Exchange Contract [Member] | Policyholder benefits and claims | Cash Flow Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Credit contracts | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0
Credit contracts | Net Derivative Gains (Losses) | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	(19)	21	10
Credit contracts | Net investment income | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Credit contracts | Policyholder benefits and claims | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	0	0
Equity market contracts | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Change in Unrealized Gain (Loss) on Hedged Item in Fair Value Hedge	0	0	0
Gains Losses Deferred In Accumulated Other Comprehensive Income Loss On Derivatives Effective Portion	0	0	0
Equity market contracts | Net Derivative Gains (Losses) | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	570	(2,584)	(1,724)
Equity market contracts | Net investment income | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	0	(1)	(6)
Equity market contracts | Policyholder benefits and claims | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	$ 0	$ (341)	$ (320)