Level 4 - Available-for-Sale Securities (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	$ 13,711	$ 14,035
Gross Unrealized Gains, fixed maturities, available-for-sale	300	53
Gross Unrealized Losses, fixed maturities, available-for-sale	(62)	(279)
Debt Securities, Available-for-sale	13,977	13,839
Non-Credit OTTI	0	(1)
Equity securities, available-for-sale, at fair value (cost: December 31, 2017 Predecessor Company - $140)		116
Amortized Cost
One year or less	430	481
Over one year through five years	1,419	1,508
Over five years through ten years	1,885	1,807
Over ten years	6,168	6,311
Subtotal	9,902	10,107
Mortgage-backed and asset-backed securities	3,809	3,928
Fair Value
One year or less	429	479
Over one year through five years	1,433	1,501
Over five years through ten years	1,926	1,783
Over ten years	6,342	6,157
Subtotal	10,130	9,920
Mortgage-backed and asset-backed securities	3,847	3,919
ABS [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	380	514
Gross Unrealized Gains, fixed maturities, available-for-sale	3	2
Gross Unrealized Losses, fixed maturities, available-for-sale	0	0
Debt Securities, Available-for-sale	383	516
Non-Credit OTTI	0	0
CDOs
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	996	971
Gross Unrealized Gains, fixed maturities, available-for-sale	9	5
Gross Unrealized Losses, fixed maturities, available-for-sale	(8)	(13)
Debt Securities, Available-for-sale	997	963
Non-Credit OTTI	0	0
CMBS
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	1,453	1,409
Gross Unrealized Gains, fixed maturities, available-for-sale	32	8
Gross Unrealized Losses, fixed maturities, available-for-sale	(1)	(7)
Debt Securities, Available-for-sale	1,481	1,407
Non-Credit OTTI	0	0
Corporate
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	7,855	7,860
Gross Unrealized Gains, fixed maturities, available-for-sale	183	19
Gross Unrealized Losses, fixed maturities, available-for-sale	(51)	(236)
Debt Securities, Available-for-sale	8,020	7,678
Non-Credit OTTI	0	(1)
Foreign government/government agencies
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	380	383
Gross Unrealized Gains, fixed maturities, available-for-sale	14	3
Gross Unrealized Losses, fixed maturities, available-for-sale	(1)	(6)
Debt Securities, Available-for-sale	390	377
Non-Credit OTTI	0	0
Municipal
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	710	738
Gross Unrealized Gains, fixed maturities, available-for-sale	21	5
Gross Unrealized Losses, fixed maturities, available-for-sale	0	(10)
Debt Securities, Available-for-sale	732	734
Non-Credit OTTI	0	0
RMBS [Member]
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	980	1,034
Gross Unrealized Gains, fixed maturities, available-for-sale	7	3
Gross Unrealized Losses, fixed maturities, available-for-sale	(1)	(4)
Debt Securities, Available-for-sale	986	1,033
Non-Credit OTTI	0	0
U.S. Treasuries
Debt Securities, Available-for-sale [Line Items]
Fixed maturities, available-for-sale, at fair value, amortized cost	957	1,126
Gross Unrealized Gains, fixed maturities, available-for-sale	31	8
Gross Unrealized Losses, fixed maturities, available-for-sale	0	(3)
Debt Securities, Available-for-sale	988	1,131
Non-Credit OTTI	$ 0	$ 0