Fair Value (Unobservable Input Reconciliation) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net Derivatives (2)
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	$ 20	$ (134)	$ 16	$ (122)
Total realized/unrealized gains (losses) included in net income (loss) (5) (6)	5	(2)	3	(10)
Total realized/unrealized gains (losses) included in AOCI	(10)	3	10	5
Purchases (7)	0	0	0	0
Sales (7)	0	0	(14)	0
Issuances (7)	0	0	0	0
Settlements (7)	0	0	0	0
Transfers into Level 3 (8)	0	0	0	0
Transfers out of Level 3 (8)	0	2	0	(4)
Balance, end of period	15	(131)	15	(131)
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	5	(2)	(11)	(11)
Changes in unrealized gains (losses) included in OCI	(10)		10
Embedded derivatives
Fair Value, Net Derivative Asset (Liability) Measured on Recurring Basis, Unobservable Input Reconciliation [Roll Forward]
Balance, beginning of period	(5,804)	(3,450)	(4,365)	(2,288)
Total realized/unrealized gains (losses) included in net income (loss) (5) (6)	(641)	(703)	(1,754)	(1,436)
Total realized/unrealized gains (losses) included in AOCI	0	0	0	0
Purchases (7)	0	0	0	0
Sales (7)	0	0	0	0
Issuances (7)	0	0	0	0
Settlements (7)	(173)	(217)	(499)	(646)
Transfers into Level 3 (8)	0	0	0	0
Transfers out of Level 3 (8)	0	0	0	0
Balance, end of period	(6,618)	(4,370)	(6,618)	(4,370)
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	(682)	(778)	(1,848)	(1,647)
Changes in unrealized gains (losses) included in OCI	0		0
Corporate
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	894	748	457	711
Total realized/unrealized gains (losses) included in net income (loss)	(1)	0	(2)	0
Total realized/unrealized gains(losses) included in AOCI	9	0	14	11
Purchases (7)	199	117	510	178
Sales (7)	(64)	(22)	(103)	(78)
Issuances (7)	0	0	0	0
Settlements (7)	0	0	0	0
Transfers into Level 3 (8)	164	49	263	147
Transfers out of Level 3 (8)	(142)	(84)	(80)	(161)
Balance, end of period	1,059	808	1,059	808
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	(1)	0
Changes in unrealized gains (losses) included in OCI	10		15
Structured Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	173	108	117	174
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	1
Total realized/unrealized gains(losses) included in AOCI	0	1	2	3
Purchases (7)	12	61	34	74
Sales (7)	(1)	(6)	(3)	(24)
Issuances (7)	0	0	0	0
Settlements (7)	0	0	0	0
Transfers into Level 3 (8)	0	29	9	92
Transfers out of Level 3 (8)	(103)	(18)	(78)	(145)
Balance, end of period	81	175	81	175
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	1
Changes in unrealized gains (losses) included in OCI	0		2
State and Political Subdivision
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	0	74	73	74
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	0
Total realized/unrealized gains(losses) included in AOCI	0	0	0	0
Purchases (7)	0	0	0	0
Sales (7)	0	(1)	0	(1)
Issuances (7)	0	0	0	0
Settlements (7)	0	0	0	0
Transfers into Level 3 (8)	0	0	0	0
Transfers out of Level 3 (8)	0	0	(73)	0
Balance, end of period	0	73	0	73
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in OCI	0		0
Equity Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	3	4	8	3
Total realized/unrealized gains (losses) included in net income (loss)	0	0	(1)	0
Total realized/unrealized gains(losses) included in AOCI	0	0	0	0
Purchases (7)	0	0	0	0
Sales (7)	0	0	0	0
Issuances (7)	0	0	0	0
Settlements (7)	0	0	0	0
Transfers into Level 3 (8)	0	0	0	1
Transfers out of Level 3 (8)	0	0	(4)	0
Balance, end of period	3	4	3	4
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in OCI	0		0
Short-term Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	0	0	5	0
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	0
Total realized/unrealized gains(losses) included in AOCI	0	0	0	0
Purchases (7)	10	0	10	0
Sales (7)	0	0	(5)	0
Issuances (7)	0	0	0	0
Settlements (7)	0	0	0	0
Transfers into Level 3 (8)	0	0	0	0
Transfers out of Level 3 (8)	0	0	0	0
Balance, end of period	10	0	10	0
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	0	0	0
Changes in unrealized gains (losses) included in OCI	0		0
Separate Account Assets (4)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance, beginning of period	3	0	3	1
Total realized/unrealized gains (losses) included in net income (loss)	0	0	0	0
Total realized/unrealized gains(losses) included in AOCI	0	0	0	0
Purchases (7)	0	0	0	0
Sales (7)	0	0	0	(1)
Issuances (7)	0	0	0	0
Settlements (7)	0	0	0	0
Transfers into Level 3 (8)	0	0	0	0
Transfers out of Level 3 (8)	0	0	0	0
Balance, end of period	3	0	3	0
Changes in unrealized gains (losses) included in net income (loss) for the instruments still held at end of period	0	$ 0	0	$ 0
Changes in unrealized gains (losses) included in OCI	$ 0		$ 0