Fair Value of Assets and Liabilities (Changes in Level 3 Assets and Liabilities) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	$ 674	$ 785	$ 671	$ 795
Purchases	23	35	46	42
Sales	(13)	(15)	(24)	(32)
Issuances	0	0	0	0
Settlements	(59)	(2)	(74)	(39)
Other	6	(11)	4	15
Transfers into Level 3	1	3	1	3
Transfers out of Level 3	(24)	0	(24)	(3)
Fair Value, end of period	624	783	624	783
Total gains (losses) (realized/unrealized):
Included in earnings	16	(12)	24	2
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	15	(15)	22	(1)
Equity securities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Equity securities | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	16	(12)	24	2
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	15	(15)	22	(1)
Equity securities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Equity securities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Equity securities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Assets supporting experience-rated contractholder liabilities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Assets supporting experience-rated contractholder liabilities | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	6	(11)	9	(13)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	12	(9)	8	(11)
Assets supporting experience-rated contractholder liabilities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Assets supporting experience-rated contractholder liabilities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Assets supporting experience-rated contractholder liabilities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	1	3	3	4
Assets supporting experience-rated contractholder liabilities | Foreign government bonds
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	29	220	225	223
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(3)	(3)	(3)	(3)
Other	0	0	(196)	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	26	221	26	221
Total gains (losses) (realized/unrealized):
Included in earnings	0	4	0	1
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	2	0	(2)
Assets supporting experience-rated contractholder liabilities | Corporate securities
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	592	468	444	462
Purchases	14	41	41	65
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(67)	(51)	(143)	(69)
Other	0	0	196	0
Transfers into Level 3	10	40	10	40
Transfers out of Level 3	(1)	0	(5)	(1)
Fair Value, end of period	553	488	553	488
Total gains (losses) (realized/unrealized):
Included in earnings	5	(10)	10	(9)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	11	(10)	6	(9)
Assets supporting experience-rated contractholder liabilities | Structured securities
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	60	664	149	722
Purchases	0	16	6	19
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(4)	(129)	(25)	(142)
Other	0	0	0	0
Transfers into Level 3	0	5	0	33
Transfers out of Level 3	0	(447)	(74)	(523)
Fair Value, end of period	57	107	57	107
Total gains (losses) (realized/unrealized):
Included in earnings	1	(2)	1	(2)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	1	(1)	1	(1)
Assets supporting experience-rated contractholder liabilities | Equity securities
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	1	5	1	4
Purchases	0	0	0	0
Sales	(1)	(1)	(1)	(1)
Issuances	0	0	0	0
Settlements	0	0	0	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	1	4	1	4
Total gains (losses) (realized/unrealized):
Included in earnings	1	0	1	1
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	1	1
Assets supporting experience-rated contractholder liabilities | All other activity
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	7	0	7
Purchases	3	24	3	43
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(2)	(26)	(2)	(45)
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	1	5	1	5
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other invested assets
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	373	144	263	137
Purchases	61	0	218	1
Sales	0	(12)	0	(12)
Issuances	0	0	0	0
Settlements	0	0	(42)	0
Other	2	(6)	(2)	(8)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	436	122	436	122
Total gains (losses) (realized/unrealized):
Included in earnings	0	(4)	(1)	4
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	(3)	(1)	2
Other invested assets | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	(4)	(1)	4
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	(3)	(1)	2
Other invested assets | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other invested assets | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other invested assets | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Other invested assets | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Short-term investments
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	168	10	89	8
Purchases	273	8	426	22
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	(153)	(14)	(227)	(26)
Other	0	(3)	0	(2)
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	288	1	288	1
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	(1)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	(1)
Short-term investments | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	(1)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	(1)
Short-term investments | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Short-term investments | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Short-term investments | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Short-term investments | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Cash equivalents
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	1	0	77	0
Purchases	0	9	1	9
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	(7)	(77)	(7)
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	1	2	1	2
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Cash equivalents | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Cash equivalents | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Cash equivalents | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Cash equivalents | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Cash equivalents | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Other assets
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	48	0	25	13
Purchases	8	0	17	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	98	0	98	0
Total gains (losses) (realized/unrealized):
Included in earnings	42	0	56	(13)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	41	0	55	(13)
Other assets | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	42	0	56	(13)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	41	0	55	(13)
Other assets | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other assets | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other assets | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Other assets | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Separate accounts assets
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	1,635	2,360	1,534	2,122
Purchases	139	253	228	490
Sales	(6)	(14)	(17)	(22)
Issuances	0	0	0	0
Settlements	(27)	(140)	(50)	(261)
Other	0	0	0	0
Transfers into Level 3	0	29	0	224
Transfers out of Level 3	(77)	(694)	(112)	(726)
Fair Value, end of period	1,708	1,816	1,708	1,816
Total gains (losses) (realized/unrealized):
Included in earnings	44	22	125	(11)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	41	21	115	(5)
Separate accounts assets | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Separate accounts assets | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Separate accounts assets | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	43	22	123	(11)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	41	21	115	(5)
Separate accounts assets | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Separate accounts assets | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	1	0	2	0
Future policy benefits
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(10,025)	(6,981)	(8,926)	(8,720)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	(298)	(287)	(588)	(574)
Settlements	0	0	0	0
Other	0	0	1	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	(12,723)	(6,585)	(12,723)	(6,585)
Total gains (losses) (realized/unrealized):
Included in earnings	(2,400)	683	(3,210)	2,709
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(2,503)	612	(3,364)	2,529
Future policy benefits | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(2,400)	683	(3,210)	2,709
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(2,503)	612	(3,364)	2,529
Future policy benefits | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Future policy benefits | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Future policy benefits | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Future policy benefits | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Policyholders' account balances
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(146)	(40)	(56)	(47)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	(73)	0	(109)	0
Settlements	0	6	0	8
Other	0	0	(3)	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	(1,047)	(42)	(1,047)	(42)
Total gains (losses) (realized/unrealized):
Included in earnings	(828)	(8)	(879)	(3)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(821)	(8)	(872)	(3)
Policyholders' account balances | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(828)	(8)	(879)	(3)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(821)	(8)	(872)	(3)
Policyholders' account balances | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Policyholders' account balances | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Policyholders' account balances | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Policyholders' account balances | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Other liabilities
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	0	(16)	0	(3)
Purchases	0	8	0	18
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Other	0	0	0	1
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	0	(18)	0	(18)
Total gains (losses) (realized/unrealized):
Included in earnings	0	(10)	0	(34)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	(10)	0	(33)
Other liabilities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	(10)	0	(34)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	(10)	0	(33)
Other liabilities | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other liabilities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Other liabilities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Other liabilities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Notes Issued by Consolidated VIEs
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	(817)	(612)	(595)	(1,196)
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	(858)	0
Settlements	0	0	638	0
Other	0	0	0	587
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	(816)	(609)	(816)	(609)
Total gains (losses) (realized/unrealized):
Included in earnings	1	3	(1)	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	1	3	(1)	0
Notes Issued by Consolidated VIEs | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	1	3	(1)	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	1	3	(1)	0
Notes Issued by Consolidated VIEs | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Notes Issued by Consolidated VIEs | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Notes Issued by Consolidated VIEs | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Notes Issued by Consolidated VIEs | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	(11)	(19)	(13)	(13)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(5)	(21)	(26)	(30)
Available-for-sale | Fixed maturities | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	18	(25)	40	(39)
Available-for-sale | Fixed maturities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	6	4	10	8
Available-for-sale | Fixed maturities | U.S. government
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	88	59	81	52
Purchases	6	8	13	15
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	94	67	94	67
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | U.S. states
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	4	5	5	5
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	(1)	0
Other	0	0	0	0
Transfers into Level 3	0	0	0	0
Transfers out of Level 3	0	0	0	0
Fair Value, end of period	4	5	4	5
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | Foreign government bonds
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	138	128	125	148
Purchases	0	0	0	0
Sales	0	0	0	0
Issuances	0	0	0	0
Settlements	0	0	0	0
Other	(2)	(4)	(1)	(3)
Transfers into Level 3	0	15	9	20
Transfers out of Level 3	(111)	0	(111)	(26)
Fair Value, end of period	24	137	24	137
Total gains (losses) (realized/unrealized):
Included in earnings	(1)	(2)	2	(2)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Available-for-sale | Fixed maturities | Corporate securities
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	2,757	2,735	2,685	2,776
Purchases	288	257	607	375
Sales	(17)	(3)	(29)	(4)
Issuances	0	0	0	0
Settlements	(225)	(286)	(604)	(455)
Other	1	(31)	(1)	(19)
Transfers into Level 3	19	69	183	129
Transfers out of Level 3	(37)	(21)	(59)	(93)
Fair Value, end of period	2,792	2,691	2,792	2,691
Total gains (losses) (realized/unrealized):
Included in earnings	6	(29)	10	(18)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(5)	(21)	(26)	(30)
Available-for-sale | Fixed maturities | Structured securities
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	1,915	6,899	1,339	6,715
Purchases	113	441	431	1,989
Sales	(47)	(278)	(47)	(344)
Issuances	0	0	0	0
Settlements	(101)	(668)	(332)	(1,317)
Other	9	(24)	7	6
Transfers into Level 3	17	62	750	1,133
Transfers out of Level 3	(1,053)	(4,759)	(1,312)	(6,494)
Fair Value, end of period	861	1,664	861	1,664
Total gains (losses) (realized/unrealized):
Included in earnings	8	(9)	25	(24)
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Trading | Fixed maturities
Fair Value, Assets And Liabilities Measured On Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, beginning of period	240	204	206	156
Purchases	36	9	74	49
Sales	(13)	(38)	(14)	(42)
Issuances	0	0	0	0
Settlements	0	(3)	0	(3)
Other	1	(2)	3	3
Transfers into Level 3	39	1	39	12
Transfers out of Level 3	0	(3)	(1)	(5)
Fair Value, end of period	296	173	296	173
Total gains (losses) (realized/unrealized):
Included in earnings	(7)	5	(11)	3
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(7)	0	(7)	4
Trading | Fixed maturities | Realized investment gains (losses), net
Total gains (losses) (realized/unrealized):
Included in earnings	0	1	0	1
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Trading | Fixed maturities | Other income
Total gains (losses) (realized/unrealized):
Included in earnings	(8)	4	(12)	2
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	(7)	0	(7)	4
Trading | Fixed maturities | Interest credited to policyholders’ account balances
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Unrealized gains (losses) for assets/liabilities still held:
Included in earnings	0	0	0	0
Trading | Fixed maturities | Included in other comprehensive income (loss)
Total gains (losses) (realized/unrealized):
Included in earnings	0	0	0	0
Trading | Fixed maturities | Net investment income
Total gains (losses) (realized/unrealized):
Included in earnings	$ 1	$ 0	$ 1	$ 0