Separation of Brighthouse (Effects of Affiliated Reinsurance on Statements of Operations) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Premiums Earned, Net [Abstract]
Premiums Earned, Net	$ 9,178	$ 8,965
Fees and Commissions [Abstract]
Insurance Commissions and Fees	1,392	1,360
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder benefits and claims	8,718	8,863
Interest Credited To Policyholder Account Balances [Abstract]
Interest Credited to Policyholders Account Balances	769	1,451
Other Expenses
Operating Expenses	3,365	3,268
Affiliated Entity [Member] | Assumed Reinsurance [Member]
Premiums Earned, Net [Abstract]
Assumed Premiums Earned	70
Fees and Commissions [Abstract]
Assumed Insurance Commissions And Fees	(1)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Assumed	55
Interest Credited To Policyholder Account Balances [Abstract]
Assumed Interest Credited To Policyholders Account Balances	3
Other Expenses
Assumed Operating Expenses	6
Affiliated Entity [Member] | Ceded Reinsurance [Member]
Premiums Earned, Net [Abstract]
Ceded Premiums Earned	(2)
Fees and Commissions [Abstract]
Ceded Insurance Commissions And Fees	(22)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Ceded	(6)
Interest Credited To Policyholder Account Balances [Abstract]
Ceded Interest Credited To Policyholders Account Balances	(12)
Other Expenses
Ceded Operating Expenses	(7)
Affiliated Entity [Member] | Reinsurance [Member]
Premiums Earned, Net [Abstract]
Premiums Earned, Net	68
Fees and Commissions [Abstract]
Insurance Commissions and Fees	(23)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder benefits and claims	49
Interest Credited To Policyholder Account Balances [Abstract]
Interest Credited to Policyholders Account Balances	(9)
Other Expenses
Operating Expenses	(1)
Brighthouse Financial, Inc | Assumed Reinsurance [Member]
Premiums Earned, Net [Abstract]
Assumed Premiums Earned	96	97
Fees and Commissions [Abstract]
Assumed Insurance Commissions And Fees	1	(4)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Assumed	78	75
Interest Credited To Policyholder Account Balances [Abstract]
Assumed Interest Credited To Policyholders Account Balances	4	4
Other Expenses
Assumed Operating Expenses	34	(30)
Brighthouse Financial, Inc | Ceded Reinsurance [Member]
Premiums Earned, Net [Abstract]
Ceded Premiums Earned	(3)	(3)
Fees and Commissions [Abstract]
Ceded Insurance Commissions And Fees	(24)	(24)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder Benefits and Claims Incurred, Ceded	(10)	(6)
Interest Credited To Policyholder Account Balances [Abstract]
Ceded Interest Credited To Policyholders Account Balances	(18)	(18)
Other Expenses
Ceded Operating Expenses	(14)	(21)
Brighthouse Financial, Inc | Reinsurance [Member]
Premiums Earned, Net [Abstract]
Premiums Earned, Net	93	94
Fees and Commissions [Abstract]
Insurance Commissions and Fees	(23)	(28)
Policyholder Benefits and Claims Incurred, Net [Abstract]
Policyholder benefits and claims	68	69
Interest Credited To Policyholder Account Balances [Abstract]
Interest Credited to Policyholders Account Balances	(14)	(14)
Other Expenses
Operating Expenses	$ 20	$ (51)