Condensed Financial Information (Parent Company) (Condensed Statements of Cash Flows) (Details) - USD ($) $ in Millions			3 Months Ended								12 Months Ended
	Mar. 25, 2019	Aug. 03, 2017	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income (loss)			$ (1,070)	$ 683	$ 384	$ (737)	$ 1,442	$ (271)	$ (239)	$ (67)	$ (740)	$ 865	$ (378)
Other, net											75	114	129
Net cash provided by (used in) operating activities											1,828	3,062	3,396
Cash flows from investing activities
Sales, maturities and repayments of fixed maturity securities											14,146	15,819	17,214
Purchases of fixed maturity securities											(16,915)	(16,460)	(18,782)
Net change in short-term investments											(1,942)	312	1,030
Net cash provided by (used in) investing activities											(7,341)	(4,538)	(3,915)
Cash flows from financing activities
Treasury stock acquired in connection with share repurchases											(442)	(105)	0
Preferred stock issued, net of issuance costs	$ 412										412	0	0
Dividends on preferred stock											(21)	0	0
Distribution to MetLife, Inc.		$ (1,800)									0	0	(1,798)
Net cash provided by (used in) financing activities											4,245	3,764	(2,852)
Cash and cash equivalents, beginning of year						4,145					4,145
Cash and cash equivalents, end of year			2,877				4,145				2,877	4,145
Supplemental disclosures of cash flow information
Net cash paid (received) for interest											187	159	155
Net cash paid (received) for income tax											16	(895)	(637)
Parent Company
Cash flows from operating activities
Net income (loss)											(740)	865	(378)
Equity in (earnings) losses of subsidiaries											602	(1,003)	566
Distribution from subsidiary											195	52	50
Other, net											(16)	7	(252)
Net cash provided by (used in) operating activities											41	(79)	(14)
Cash flows from investing activities
Sales, maturities and repayments of fixed maturity securities											194	3	510
Purchases of fixed maturity securities											(4)	0	(749)
Capital contributions to subsidiary											(412)	(208)	(1,300)
Net change in short-term investments											(455)	0	0
Net cash provided by (used in) investing activities											(677)	(205)	(1,539)
Cash flows from financing activities
Long-term and short-term debt issued											2,156	893	3,724
Long-term and short-term debt repaid											(1,716)	(351)	0
Debt issuance costs											0	(12)	(39)
Treasury stock acquired in connection with share repurchases											(442)	(105)	0
Preferred stock issued, net of issuance costs											412	0	0
Dividends on preferred stock											(21)	0	0
Distribution to MetLife, Inc.											0	0	(1,798)
Credit facility fees											(2)	(6)	(8)
Net cash provided by (used in) financing activities											387	419	1,879
Change in cash and cash equivalents											(249)	135	326
Cash and cash equivalents, beginning of year						$ 461				$ 326	461	326	0
Cash and cash equivalents, end of year			$ 212				$ 461				212	461	326
Supplemental disclosures of cash flow information
Net cash paid (received) for interest											187	158	67
Cash received from MetLife, Inc. for income tax											0	(7)	0
Income tax paid (received) by Brighthouse Financial, Inc.											(4)	1	1
Net cash paid (received) for income tax											$ (4)	$ (6)	$ 1