Derivatives (Effects on the Consolidated Statement of Operations and Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	$ 5,568	$ 4,729	$ 16,162	$ 11,877
Net investment gains (losses)	(84)	(20)	1,655	(77)
Derivative, Gain (Loss) on Derivative, Net	(218)	(581)	(2,032)	2,910
Policyholder Benefits and Claims Incurred, Net	(10,103)	(10,000)	(30,031)	(27,689)
Policyholder Account Balance, Interest Expense	(1,287)	(1,416)	(4,153)	(3,458)
Operating Expenses	3,284	3,470	9,315	9,726
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	(2)	(6)	(32)	(12)
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	(523)	(1,251)	(3,503)	2,936
Policyholder Benefits and Claims Incurred, Net	9	97	252	70
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	5	(3)	7	1
Net investment gains (losses)	(2)	(1)	(11)	(34)
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	(5)	(15)	(39)	(24)
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	16	11	47	27
Net investment gains (losses)	3	52	43	139
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	1	1	3	3
Other Comprehensive Income (Loss), before Tax	678	(1,303)	107	1,843
Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	14	(37)	89	59
Nonperformance Risk [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net	3	(12)	(48)	63
Foreign Exchange Forward [Member] | Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax				70
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	12	(29)	58
Interest Rate Contract | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	14	9	41	24
Net investment gains (losses)	6	10	54	58
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	1	1	2	2
Other Comprehensive Income (Loss), before Tax	(21)	(20)	(97)	(84)
Credit forwards [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	0	0	0	0
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Other Comprehensive Income (Loss), before Tax	0	0	0	0
Currency Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	2	2	6	3
Net investment gains (losses)	(259)	435	(383)	271
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	1	1
Other Comprehensive Income (Loss), before Tax	257	(437)	376	(275)
Derivative [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	0	0	0	0
Net investment gains (losses)	(2)	(4)	(6)	(38)
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Derivative [Member] | Interest rate swaps | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	1	1	4	(11)
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	53	154	418	(589)
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Derivative [Member] | Currency Swap [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	28	(50)	40	17
Net investment gains (losses)	(9)	44	(144)	58
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Debt Securities [Member] | Interest rate swaps | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	(2)	0	(4)	9
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	48	139	379	(613)
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Debt Securities [Member] | Currency Swap [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	(22)	46	(33)	(14)
Net investment gains (losses)	9	(41)	139	(54)
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Non-derivative [Domain] [Member] | Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	2	(8)	31	(11)
Foreign Currency Gain (Loss) [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	0	0	0	0
Net investment gains (losses)	256	(393)	372	(190)
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Other Comprehensive Income (Loss), before Tax	0	0	0	0
Accumulated Other Comprehensive Income (Loss) | Credit forwards [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	20	(28)	(52)	(52)
Accumulated Other Comprehensive Income (Loss) | Currency Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	398	(615)	567	554
Accumulated Other Comprehensive Income (Loss) | Interest rate swaps | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	24	(203)	(687)	1,700
Foreign Exchange [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	0	0	0	0
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	(128)	(190)	(734)	(187)
Policyholder Benefits and Claims Incurred, Net	(2)	2	1	(7)
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Credit derivatives — purchased | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	0	0	0	0
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	4	(8)	16	4
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Credit derivatives — written | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	0	0	0	0
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	(2)	(9)	33	(158)
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Equity Market Risk [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	(1)	(6)	(33)	(6)
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	47	(499)	(992)	17
Policyholder Benefits and Claims Incurred, Net	(5)	90	202	19
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Interest Rate Risk [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	(1)	0	1	(6)
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	(379)	(601)	(1,993)	3,364
Policyholder Benefits and Claims Incurred, Net	12	9	51	(58)
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Foreign Currency Gain (Loss) [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	0	0	0	0
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	(65)	56	167	(104)
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Policyholder Account Balance, Interest Expense	0	0	0	0
Operating Expenses	0	0	0	0
Net Derivative Gain (Loss) [Member] | Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	62	50	128	196
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	258	262	755	617
Policyholder Benefits and Claims Incurred, Net	(55)	(52)	(160)	(135)
Policyholder Account Balance, Interest Expense	(43)	(36)	(120)	(118)
Operating Expenses	0	0	0	0
Other Comprehensive Income (Loss), before Tax	0	0	0	0
Net Embedded Derivatives
Derivative Instruments, Gain (Loss) [Line Items]
Derivative, Gain (Loss) on Derivative, Net	47	408	716	(643)
Policyholder Benefits and Claims Incurred, Net	0	0	0	0
Effects of Derivatives on Consolidated Statements of Operations and Comprehensive Income (Loss) [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	81	52	150	212
Net investment gains (losses)	1	51	32	105
Policyholder Benefits and Claims Incurred, Net	(41)	60	131	(181)
Policyholder Account Balance, Interest Expense	43	36	120	118
Operating Expenses	1	1	3	3
Other Comprehensive Income (Loss), before Tax	$ 692	$ (1,340)	$ 196	$ 1,902