Condensed Financial Information Condensed Financial Information (Parent Company) (Condensed Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Investments [Abstract]
Available-for-sale Securities, Debt Securities	$ 63,333	$ 59,899
Available-for-sale Securities, Equity Securities	232	300
Mortgage Loans on Real Estate	10,640	9,290
Policy loans	1,106	1,093
Real estate joint ventures	433	215
Other Limited Partnership Interests	1,667	1,639
Short-term investments, principally at estimated fair value	269	1,272
Other invested assets, at estimated fair value	2,448	5,029
Total investments	80,128	78,737
Cash and Cash Equivalents, at Carrying Value	1,363	5,057	$ 1,507	$ 1,553
Accrued Investment Income Receivable	575	668
Premiums, reinsurance and other receivables	12,918	13,853
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net	5,623	6,339	5,777
Current income tax recoverable	735	736
Other Assets	547	689
Separate Account Assets	110,156	105,346
Total assets	212,045	211,425
Liabilities
Future policy benefits	35,715	32,752
Policyholder account balances	37,069	36,579
Other policy-related balances	2,720	2,712
Payables For Collateral Under Securities Loaned And Other Transactions	4,158	7,371
Deferred income tax liability	894	2,451
Other Liabilities	4,419	5,445
Separate Accounts, Liability	110,156	105,346
Total liabilities	195,177	194,560
Stockholders' Equity Attributable to Parent [Abstract]
Common stock, par value $25,000 per share; 4,000 shares authorized; 3,000 shares issued and outstanding	75	75
Additional Paid in Capital	19,073	18,461
Retained Earnings (Accumulated Deficit)	(4,132)	(2,919)
Accumulated Other Comprehensive Income (Loss), Net of Tax	1,837	1,248	1,594	2,622
Total Brighthouse Life Insurance Company's stockholder's equity	16,853	16,865
Total liabilities and equity	212,045	211,425
Parent Company
Investments [Abstract]
Available-for-sale Securities, Debt Securities	55,180	51,880
Available-for-sale Securities, Equity Securities	210	300
Mortgage Loans on Real Estate	10,127	8,746
Policy loans	1,106	1,093
Real estate joint ventures	419	200
Other Limited Partnership Interests	1,662	1,632
Short-term investments, principally at estimated fair value	269	926
Investment in subsidiaries	5,681	7,338
Other invested assets, at estimated fair value	2,291	3,712
Total investments	76,945	75,827
Cash and Cash Equivalents, at Carrying Value	1,249	1,881	$ 1,379	$ 1,197
Accrued Investment Income Receivable	511	591
Premiums, reinsurance and other receivables	9,658	10,397
Due from Affiliates	10,397	9,703
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net	5,123	5,274
Current income tax recoverable	39	454
Deferred Tax Assets, Net, Noncurrent	1,247	1,016
Other Assets	536	667
Separate Account Assets	105,135	100,588
Total assets	210,840	206,398
Liabilities
Future policy benefits	35,003	31,684
Policyholder account balances	36,034	35,588
Other policy-related balances	3,347	3,384
Payables For Collateral Under Securities Loaned And Other Transactions	4,153	7,362
Notes Payable, Related Parties	0	744
Other Liabilities	10,315	10,183
Separate Accounts, Liability	105,135	100,588
Total liabilities	193,987	189,533
Stockholders' Equity Attributable to Parent [Abstract]
Common stock, par value $25,000 per share; 4,000 shares authorized; 3,000 shares issued and outstanding	75	75
Additional Paid in Capital	19,073	18,461
Retained Earnings (Accumulated Deficit)	(4,132)	(2,919)
Accumulated Other Comprehensive Income (Loss), Net of Tax	1,837	1,248
Total Brighthouse Life Insurance Company's stockholder's equity	16,853	16,865
Total liabilities and equity	$ 210,840	$ 206,398