Derivative Instruments (Gross Notional Amount and Fair Value of Derivatives Contracts) (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Derivative [Line Items]
Notional	$ 379,860	$ 405,644
Assets	14,386	10,480
Liabilities	(7,536)	(5,408)
Net Embedded Derivative Liability	14,035	8,959
Derivatives Designated as Hedge Accounting Instruments:
Derivative [Line Items]
Notional	27,669	25,931
Assets	2,121	1,877
Liabilities	(433)	(427)
Derivatives Designated as Hedge Accounting Instruments: | Interest Rate Swaps
Derivative [Line Items]
Notional	3,257	3,885
Assets	628	305
Liabilities	(73)	(67)
Derivatives Designated as Hedge Accounting Instruments: | Interest Rate Forwards
Derivative [Line Items]
Notional	205	600
Assets	4	26
Liabilities	(1)	0
Derivatives Designated as Hedge Accounting Instruments: | Foreign Currency Forwards
Derivative [Line Items]
Notional	1,461	722
Assets	22	26
Liabilities	(57)	(2)
Derivatives Designated as Hedge Accounting Instruments: | Foreign Currency Swaps
Derivative [Line Items]
Notional	22,746	20,724
Assets	1,467	1,520
Liabilities	(302)	(358)
Derivatives Not Qualifying as Hedge Accounting Instruments:
Derivative [Line Items]
Notional	352,191	379,713
Assets	12,265	8,603
Liabilities	(7,103)	(4,981)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate Swaps
Derivative [Line Items]
Notional	141,162	140,963
Assets	10,249	5,792
Liabilities	(4,861)	(3,435)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate Forwards
Derivative [Line Items]
Notional	2,218	5,049
Assets	18	72
Liabilities	(3)	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Foreign Currency Forwards
Derivative [Line Items]
Notional	26,604	19,849
Assets	208	246
Liabilities	(214)	(138)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Foreign Currency Options
Derivative [Line Items]
Notional	0	2
Assets	0	0
Liabilities	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Foreign Currency Swaps
Derivative [Line Items]
Notional	13,874	13,784
Assets	740	773
Liabilities	(345)	(421)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate Futures
Derivative [Line Items]
Notional	17,095	13,991
Assets	4	23
Liabilities	(38)	(2)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Interest Rate Options
Derivative [Line Items]
Notional	16,496	24,002
Assets	339	147
Liabilities	(238)	(314)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Credit Default Swaps
Derivative [Line Items]
Notional	798	5,207
Assets	21	33
Liabilities	0	(23)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity Futures
Derivative [Line Items]
Notional	1,802	1,141
Assets	0	0
Liabilities	(3)	(8)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Equity Options
Derivative [Line Items]
Notional	32,657	58,693
Assets	679	384
Liabilities	(765)	(554)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Total Return Swaps
Derivative [Line Items]
Notional	18,218	17,309
Assets	6	1,131
Liabilities	(636)	(86)
Derivatives Not Qualifying as Hedge Accounting Instruments: | Other
Derivative [Line Items]
Notional	1,258	508
Assets	0	0
Liabilities	0	0
Derivatives Not Qualifying as Hedge Accounting Instruments: | Synthetic GICs
Derivative [Line Items]
Notional	80,009	79,215
Assets	1	2
Liabilities	$ 0	$ 0