Reinsurance (Related Party Narrative) (Details) - USD ($)		3 Months Ended		6 Months Ended	12 Months Ended
	Apr. 30, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	May 01, 2017	Jan. 01, 2017	Dec. 01, 2016	Nov. 01, 2016	Apr. 01, 2016	Dec. 31, 2015
Other invested assets, at estimated fair value					$ 3,037,000,000	$ 2,519,000,000
Reinsurance Disclosures [Abstract]
Embedded Derivative, Fair Value of Embedded Derivative Liability					2,516,000,000	2,234,000,000
Other liabilities					3,455,000,000	4,419,000,000
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		$ 5,057,000,000			3,494,000,000	1,363,000,000	$ 5,057,000,000						$ 1,507,000,000
Deferred Policy Acquisition Costs		5,667,000,000			4,518,000,000	5,015,000,000	5,667,000,000						$ 5,066,000,000
Premiums, reinsurance and other receivables					13,113,000,000	12,918,000,000
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net		$ 6,339,000,000			5,086,000,000	5,623,000,000	6,339,000,000
Other Assets					509,000,000	547,000,000
Future policy benefits					35,588,000,000	35,715,000,000
Policyholder Account Balances					39,330,000,000	37,069,000,000
Embedded Derivative, Fair Value of Embedded Derivative Asset					228,000,000	175,000,000
Reinsurance recoverables					12,300,000,000	9,100,000,000
Income (loss) before provision for income tax					1,121,000,000	(1,621,000,000)	(4,465,000,000)
Deposit Contracts, Assets					1,400,000,000	1,400,000,000
Deposit Contracts, Liabilities					1,400,000,000	445,000,000
Affiliated Entity
Reinsurance Disclosures [Abstract]
Deposit Contracts, Assets					0	1,300,000,000
Deposit Contracts, Liabilities					174,000,000	198,000,000
Affiliated Entity | Assumed guaranteed minimum benefits
Reinsurance Disclosures [Abstract]
Embedded Derivative, Fair Value of Embedded Derivative Liability					0	0
Net derivatives gains (losses)					0	110,000,000	(27,000,000)
Affiliated Entity | Ceded guaranteed minimum income benefits
Reinsurance Disclosures [Abstract]
Net derivatives gains (losses)						(126,000,000)	$ 46,000,000
Embedded Derivative, Fair Value of Embedded Derivative Asset					0	2,000,000
Affiliated Entity | Recapture MLUS [Member]
Reinsurance Disclosures [Abstract]
Cash, Cash Equivalents, and Short-term Investments												$ 4,300,000,000
Premiums, reinsurance and other receivables												(4,000,000,000)
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net												$ 87,000,000
Income (loss) before provision for income tax			$ 246,000,000
Maximum | Affiliated Entity | Ceded guaranteed minimum income benefits
Reinsurance Disclosures [Abstract]
Net derivatives gains (losses)					1,000,000
PWL [Member]
Percentage Of Participating Whole Life Insurance Policies		90.00%					90.00%
Other invested assets, at estimated fair value		$ (713,000,000)					$ (713,000,000)
Reinsurance Disclosures [Abstract]
Other liabilities		(43,000,000)					(43,000,000)
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net		(95,000,000)					(95,000,000)
Future policy benefits		(654,000,000)					(654,000,000)
Income (loss) before provision for income tax		(72,000,000)
Ceded Reinsurance [Member]
Reinsurance Disclosures [Abstract]
Other liabilities					655,000,000	701,000,000
Premiums, reinsurance and other receivables					12,669,000,000	12,508,000,000
Policyholder Account Balances					0	0
Ceded Reinsurance [Member] | Affiliated Entity
Reinsurance Disclosures [Abstract]
Other liabilities					0	401,000,000
Premiums, reinsurance and other receivables					0	3,254,000,000
Policyholder Account Balances					0	0
Metropolitan Life Insurance Company [Member] | Affiliated Entity | Life and Other [Member]
Reinsurance Disclosures [Abstract]
Cash, Cash Equivalents, and Short-term Investments								$ 214,000,000
Premiums, reinsurance and other receivables								$ (189,000,000)
Income (loss) before provision for income tax	$ 17,000,000
Metropolitan Life Insurance Company [Member] | Affiliated Entity | BHL Recapture GMIB [Member]
Reinsurance Disclosures [Abstract]
Cash, Cash Equivalents, and Short-term Investments									$ (568,000,000)
Premiums, reinsurance and other receivables									140,000,000
Future policy benefits									(106,000,000)
Policyholder Account Balances									(460,000,000)
Income (loss) before provision for income tax				$ 89,000,000
Brighthouse Life Insurance Company NY [Member] | Affiliated Entity | Affiliate Recapture Variable Annuities [Member]
Reinsurance Disclosures [Abstract]
Other liabilities									(359,000,000)
Cash, Cash Equivalents, and Short-term Investments									150,000,000
Future policy benefits									45,000,000
Policyholder Account Balances									168,000,000
New England Life Insurance Company [Member] | Affiliated Entity | Assumed guaranteed minimum benefits
Reinsurance Disclosures [Abstract]
Embedded Derivative, Fair Value of Embedded Derivative Liability					386,000,000	436,000,000
Net derivatives gains (losses)					53,000,000	67,000,000	6,000,000
New England Life Insurance Company [Member] | Affiliated Entity | Affiliate Recapture Variable Annuities [Member]
Reinsurance Disclosures [Abstract]
Other liabilities									(68,000,000)
Cash, Cash Equivalents, and Short-term Investments									184,000,000
Future policy benefits									34,000,000
Policyholder Account Balances									$ 219,000,000
Brighthouse Life Insurance Co of NY [Member] | Affiliated Entity | SPDARecapture [Member]
Reinsurance Disclosures [Abstract]
Cash, Cash Equivalents, and Short-term Investments											$ 933,000,000
Deferred Policy Acquisition Costs											23,000,000
Premiums, reinsurance and other receivables											$ (923,000,000)
Income (loss) before provision for income tax		22,000,000
Brighthouse Life Insurance Co of NY [Member] | Affiliated Entity | MRVTermRecapture [Member]
Reinsurance Disclosures [Abstract]
Other liabilities										$ (158,000,000)
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents		(27,000,000)					$ (27,000,000)
Premiums, reinsurance and other receivables										$ (94,000,000)
Income (loss) before provision for income tax		$ 24,000,000
Ceded Credit Risk, Unsecured [Member]
Reinsurance Disclosures [Abstract]
Reinsurance recoverables					5,000,000,000	2,400,000,000
Ceded Credit Risk, Unsecured [Member] | Affiliated Entity
Reinsurance Disclosures [Abstract]
Reinsurance recoverables					$ 0	$ 2,500,000,000