Derivatives (Effects on the Consolidated Statement of Operations and Comprehensive Income (Loss)) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	$ 5,280	$ 4,087	$ 10,594	$ 7,148
Net investment gains (losses)	1,605	231	1,739	(57)
Derivative, Gain (Loss) on Derivative, Net	421	(710)	(1,814)	3,491
Policyholder Benefits and Claims Incurred, Net	(9,405)	(8,667)	(19,928)	(17,689)
Policyholder Account Balance, Interest Expense	(1,515)	(1,962)	(2,866)	(2,042)
Operating Expenses	2,881	2,983	6,031	6,256
Not Designated as Hedging Instrument [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	(15)	(2)	(30)	(6)
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	180	(1,289)	(2,980)	4,187
Policyholder Benefits and Claims Incurred, Net	95	81	243	167
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	1	3	2	4
Net investment gains (losses)	(2)	(15)	(9)	(33)
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	(5)	(14)	(34)	(9)
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	10	31	16
Net investment gains (losses)	19	79	40	87
Derivative, Gain (Loss) on Derivative, 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	697	(979)	(571)	3,146
Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	19	(12)	75	96
Nonperformance Risk [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net	(8)	(110)	(51)	75
Foreign Exchange Forward [Member] | Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax				99
Designated as Hedging Instrument [Member] | Net Investment Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	17	(11)	46
Interest Rate Contract | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	15	9	27	15
Net investment gains (losses)	19	42	48	48
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	(34)	(51)	(76)	(64)
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	1	1	4	1
Net investment gains (losses)	95	287	(124)	(164)
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	1	1
Other Comprehensive Income (Loss), before Tax	(97)	(289)	119	162
Derivative [Member] | Fair Value Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Net investment income	0	0	0	0
Net investment gains (losses)	(2)	(14)	(4)	(34)
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	0	(1)	3	(12)
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	0	0	0	0
Policyholder Benefits and Claims Incurred, Net	(237)	31	365	(743)
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	(1)	(5)	12	67
Net investment gains (losses)	(7)	2	(135)	14
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	1	4	(2)	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	(242)	17	331	(752)
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	1	5	(11)	(60)
Net investment gains (losses)	7	(3)	130	(13)
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	(1)	29	(3)
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)	(95)	(250)	116	203
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	(4)	(86)	(72)	(24)
Accumulated Other Comprehensive Income (Loss) | Currency Swap [Member] | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	322	(445)	169	1,169
Accumulated Other Comprehensive Income (Loss) | Interest rate swaps | Cash Flow Hedging [Member]
Derivative Instruments, Gain (Loss) [Line Items]
Other Comprehensive Income (Loss), before Tax	510	(108)	(711)	1,903
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	(123)	(132)	(606)	3
Policyholder Benefits and Claims Incurred, Net	0	(1)	3	(9)
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	(7)	(61)	12	12
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	30	162	35	(149)
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	(15)	0	(32)	0
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	(363)	(1,043)	(1,039)	516
Policyholder Benefits and Claims Incurred, Net	103	99	207	109
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	0	(2)	2	(6)
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	636	(212)	(1,614)	3,965
Policyholder Benefits and Claims Incurred, Net	(8)	(19)	39	(67)
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	7	(3)	232	(160)
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	27	69	66	146
Net investment gains (losses)	0	0	0	0
Derivative, Gain (Loss) on Derivative, Net	245	208	497	355
Policyholder Benefits and Claims Incurred, Net	(52)	(44)	(105)	(83)
Policyholder Account Balance, Interest Expense	(38)	(38)	(77)	(82)
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	(4)	371	669	(1,051)
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	29	80	69	160
Net investment gains (losses)	17	64	31	54
Policyholder Benefits and Claims Incurred, Net	48	51	172	(241)
Policyholder Account Balance, Interest Expense	38	38	77	82
Operating Expenses	1	1	2	2
Other Comprehensive Income (Loss), before Tax	$ 716	$ (991)	$ (496)	$ 3,242