Segment Information (Operating Results) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2018	Mar. 31, 2018	Jun. 30, 2019	Jun. 30, 2018
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	$ 439		$ (229)		$ (536)	$ (253)
Provision for income tax expense (benefit)	76		(65)		(145)	(87)
Post-tax adjusted earnings	363	$ (754)	(164)	$ (2)	(391)	(166)
Less: Net income (loss) attributable to noncontrolling interests	1		0		1	0
Net investment gains (losses)	56		(74)		46	(78)
Net derivative gains (losses)	108		(278)		(1,202)	(565)
Other adjustments to net income	69		70		131	149
Net income (loss) attributable to Brighthouse Life Insurance Company	362		(164)		(392)	(166)
Annuities
Segment Reporting Information [Line Items]
Interest revenue	468		374		886	733
Interest expense	0		0		0	0
Life
Segment Reporting Information [Line Items]
Interest revenue	101		92		183	180
Interest expense	0		0		0	0
Run-off
Segment Reporting Information [Line Items]
Interest revenue	339		314		615	657
Interest expense	0		0		0	0
Corporate & Other
Segment Reporting Information [Line Items]
Interest revenue	10		7		22	17
Interest expense	16		1		26	2
Operating Segments
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	321		235		581	601
Provision for income tax expense (benefit)	52		33		90	93
Post-tax adjusted earnings	269		202		491	508
Less: Net income (loss) attributable to noncontrolling interests	1		0		1	0
Adjusted earnings	268		202		490	508
Operating Segments | Annuities
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	321		255		668	510
Provision for income tax expense (benefit)	59		43		122	87
Post-tax adjusted earnings	262		212		546	423
Less: Net income (loss) attributable to noncontrolling interests	0		0		0	0
Adjusted earnings	262		212		546	423
Operating Segments | Life
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	72		26		97	90
Provision for income tax expense (benefit)	15		6		20	18
Post-tax adjusted earnings	57		20		77	72
Less: Net income (loss) attributable to noncontrolling interests	0		0		0	0
Adjusted earnings	57		20		77	72
Operating Segments | Run-off
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	2		(8)		(44)	56
Provision for income tax expense (benefit)	0		(2)		(10)	11
Post-tax adjusted earnings	2		(6)		(34)	45
Less: Net income (loss) attributable to noncontrolling interests	0		0		0	0
Adjusted earnings	2		(6)		(34)	45
Operating Segments | Corporate & Other
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(74)		(38)		(140)	(55)
Provision for income tax expense (benefit)	(22)		(14)		(42)	(23)
Post-tax adjusted earnings	(52)		(24)		(98)	(32)
Less: Net income (loss) attributable to noncontrolling interests	1		0		1	0
Adjusted earnings	(53)		(24)		(99)	(32)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Provision for income tax expense (benefit)	(24)		98		235	180
Net investment gains (losses)	56		(74)		46	(78)
Net derivative gains (losses)	108		(278)		(1,202)	(565)
Other adjustments to net income	$ (46)		$ (112)		$ 39	$ (211)