Segment Information (Operating Results) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	$ 6,104	$ (975)
Provision for income tax expense (benefit)	1,265	(221)
Post-tax adjusted earnings	4,839	(754)
Less: Net income (loss) attributable to noncontrolling interests	0	0
Net investment gains (losses)	(19)	(10)
Net derivative gains (losses)	6,747	(1,310)
Other adjustments to net income (loss)	84	62
Net income (loss) attributable to Brighthouse Life Insurance Company	4,839	(754)
Annuities
Segment Reporting Information [Line Items]
Interest revenue	458	418
Interest expense	0	0
Life
Segment Reporting Information [Line Items]
Interest revenue	100	82
Interest expense	0	0
Run-off
Segment Reporting Information [Line Items]
Interest revenue	324	276
Interest expense	0	0
Corporate & Other
Segment Reporting Information [Line Items]
Interest revenue	16	12
Interest expense	17	10
Operating Segments
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	232	260
Provision for income tax expense (benefit)	32	38
Post-tax adjusted earnings	200	222
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	200	222
Operating Segments | Annuities
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	383	347
Provision for income tax expense (benefit)	72	63
Post-tax adjusted earnings	311	284
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	311	284
Operating Segments | Life
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	21	25
Provision for income tax expense (benefit)	4	5
Post-tax adjusted earnings	17	20
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	17	20
Operating Segments | Run-off
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(89)	(46)
Provision for income tax expense (benefit)	(19)	(10)
Post-tax adjusted earnings	(70)	(36)
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	(70)	(36)
Operating Segments | Corporate & Other
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(83)	(66)
Provision for income tax expense (benefit)	(25)	(20)
Post-tax adjusted earnings	(58)	(46)
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	(58)	(46)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Provision for income tax expense (benefit)	(1,233)	259
Net investment gains (losses)	(19)	(10)
Net derivative gains (losses)	6,747	(1,310)
Other adjustments to net income (loss)	$ (856)	$ 85