Segment Information (Operating Results) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	$ 708	$ (407)			$ 172	$ (660)
Provision for income tax expense (benefit)	99	(108)			(46)	(195)
Post-tax adjusted earnings	609	(299)	$ (391)	$ (166)	218	(465)
Less: Net income (loss) attributable to noncontrolling interests	0	0			1	0
Net investment gains (losses)	14	(42)			60	(120)
Net derivative gains (losses)	984	(665)			(218)	(1,230)
Other adjustments to net income	68	73			199	222
Net income (loss) attributable to Brighthouse Life Insurance Company	609	(299)			217	(465)
Annuities
Segment Reporting Information [Line Items]
Interest revenue	458	395			1,344	1,128
Interest expense	0	0			0	0
Life
Segment Reporting Information [Line Items]
Interest revenue	101	96			284	276
Interest expense	0	0			0	0
Run-off
Segment Reporting Information [Line Items]
Interest revenue	327	322			942	979
Interest expense	0	0			0	0
Corporate & Other
Segment Reporting Information [Line Items]
Interest revenue	18	12			40	29
Interest expense	17	0			43	2
Operating Segments
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(278)	266			303	867
Provision for income tax expense (benefit)	(109)	32			(19)	125
Post-tax adjusted earnings	(169)	234			322	742
Less: Net income (loss) attributable to noncontrolling interests	0	0			1	0
Adjusted earnings	(169)	234			321	742
Operating Segments | Annuities
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	247	469			915	979
Provision for income tax expense (benefit)	50	81			172	168
Post-tax adjusted earnings	197	388			743	811
Less: Net income (loss) attributable to noncontrolling interests	0	0			0	0
Adjusted earnings	197	388			743	811
Operating Segments | Life
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	88	52			185	142
Provision for income tax expense (benefit)	18	10			38	28
Post-tax adjusted earnings	70	42			147	114
Less: Net income (loss) attributable to noncontrolling interests	0	0			0	0
Adjusted earnings	70	42			147	114
Operating Segments | Run-off
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(543)	(135)			(587)	(79)
Provision for income tax expense (benefit)	(117)	(29)			(127)	(18)
Post-tax adjusted earnings	(426)	(106)			(460)	(61)
Less: Net income (loss) attributable to noncontrolling interests	0	0			0	0
Adjusted earnings	(426)	(106)			(460)	(61)
Operating Segments | Corporate & Other
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(70)	(120)			(210)	(175)
Provision for income tax expense (benefit)	(60)	(30)			(102)	(53)
Post-tax adjusted earnings	(10)	(90)			(108)	(122)
Less: Net income (loss) attributable to noncontrolling interests	0	0			1	0
Adjusted earnings	(10)	(90)			(109)	(122)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Provision for income tax expense (benefit)	(208)	140			27	320
Net investment gains (losses)	14	(42)			60	(120)
Net derivative gains (losses)	984	(665)			(218)	(1,230)
Other adjustments to net income	$ (12)	$ 34			$ 27	$ (177)