Separation of Brighthouse (Effects of Affiliated Reinsurance on Statements of Operations) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Premiums Earned, Net [Abstract]
Premiums Earned, Net	$ 10,242	$ 10,876	$ 34,573	$ 29,421
Insurance Services Revenue [Abstract]
Insurance Commissions and Fees	1,343	1,428	4,105	4,152
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder benefits and claims	10,080	10,728	33,664	29,018
Interest Credited To Policyholder Account Balances [Abstract]
Interest Credited to Policyholders Account Balances	1,334	1,338	3,527	4,081
Other Expenses
Operating Expenses	3,469	3,318	10,319	9,869
Affiliated Entity [Member] | Assumed Reinsurance [Member]
Premiums Earned, Net [Abstract]
Assumed Premiums Earned		70		70
Insurance Services Revenue [Abstract]
Assumed Insurance Commissions And Fees		(1)		(1)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Assumed		55		55
Interest Credited To Policyholder Account Balances [Abstract]
Assumed Interest Credited To Policyholders Account Balances		3		3
Other Expenses
Assumed Operating Expenses		6		6
Affiliated Entity [Member] | Ceded Reinsurance [Member]
Premiums Earned, Net [Abstract]
Ceded Premiums Earned		(2)		(2)
Insurance Services Revenue [Abstract]
Ceded Insurance Commissions And Fees		(22)		(22)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Ceded		(6)		(6)
Interest Credited To Policyholder Account Balances [Abstract]
Ceded Interest Credited To Policyholders Account Balances		(12)		(12)
Other Expenses
Ceded Operating Expenses		(7)		(7)
Affiliated Entity [Member] | Reinsurance [Member]
Premiums Earned, Net [Abstract]
Premiums Earned, Net		68		68
Insurance Services Revenue [Abstract]
Insurance Commissions and Fees		(23)		(23)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder benefits and claims		49		49
Interest Credited To Policyholder Account Balances [Abstract]
Interest Credited to Policyholders Account Balances		(9)		(9)
Other Expenses
Operating Expenses		(1)		(1)
Brighthouse Financial, Inc | Assumed Reinsurance [Member]
Premiums Earned, Net [Abstract]
Assumed Premiums Earned	96	36	297	248
Insurance Services Revenue [Abstract]
Assumed Insurance Commissions And Fees	(4)	(1)	(6)	(6)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Assumed	81	30	243	196
Interest Credited To Policyholder Account Balances [Abstract]
Assumed Interest Credited To Policyholders Account Balances	3	1	10	10
Other Expenses
Assumed Operating Expenses	15	4	80	10
Brighthouse Financial, Inc | Ceded Reinsurance [Member]
Premiums Earned, Net [Abstract]
Ceded Premiums Earned	(3)	1	(9)	(7)
Insurance Services Revenue [Abstract]
Ceded Insurance Commissions And Fees	(23)	(8)	(67)	(55)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Ceded	(5)	(3)	(15)	(16)
Interest Credited To Policyholder Account Balances [Abstract]
Ceded Interest Credited To Policyholders Account Balances	(18)	(6)	(53)	(42)
Other Expenses
Ceded Operating Expenses	(4)	(3)	(22)	(28)
Brighthouse Financial, Inc | Reinsurance [Member]
Premiums Earned, Net [Abstract]
Premiums Earned, Net	93	37	288	241
Insurance Services Revenue [Abstract]
Insurance Commissions and Fees	(27)	(9)	(73)	(61)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder benefits and claims	76	27	228	180
Interest Credited To Policyholder Account Balances [Abstract]
Interest Credited to Policyholders Account Balances	(15)	(5)	(43)	(32)
Other Expenses
Operating Expenses	$ 11	$ 1	$ 58	$ (18)