Segment Information (Operating Results) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	$ (975)	$ (24)
Provision for income tax expense (benefit)	(221)	(22)
Post-tax adjusted earnings	(754)	(2)
Less: Net income (loss) attributable to noncontrolling interests	0	0
Net investment gains (losses)	(10)	(4)
Net derivative gains (losses)	(1,310)	(287)
Other adjustments to net income	62	79
Net income (loss) attributable to Brighthouse Life Insurance Company	(754)	(2)
Annuities
Segment Reporting Information [Line Items]
Interest revenue	418	359
Interest expense	0	0
Life
Segment Reporting Information [Line Items]
Interest revenue	82	88
Interest expense	0	0
Run-off
Segment Reporting Information [Line Items]
Interest revenue	276	343
Interest expense	0	0
Corporate & Other
Segment Reporting Information [Line Items]
Interest revenue	12	10
Interest expense	10	1
Operating Segments
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	260	366
Provision for income tax expense (benefit)	38	60
Post-tax adjusted earnings	222	306
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	222	306
Operating Segments | Annuities
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	347	255
Provision for income tax expense (benefit)	63	44
Post-tax adjusted earnings	284	211
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	284	211
Operating Segments | Life
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	25	64
Provision for income tax expense (benefit)	5	12
Post-tax adjusted earnings	20	52
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	20	52
Operating Segments | Run-off
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(46)	64
Provision for income tax expense (benefit)	(10)	13
Post-tax adjusted earnings	(36)	51
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	(36)	51
Operating Segments | Corporate & Other
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(66)	(17)
Provision for income tax expense (benefit)	(20)	(9)
Post-tax adjusted earnings	(46)	(8)
Less: Net income (loss) attributable to noncontrolling interests	0	0
Adjusted earnings	(46)	(8)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Provision for income tax expense (benefit)	259	82
Net investment gains (losses)	(10)	(4)
Net derivative gains (losses)	(1,310)	(287)
Other adjustments to net income	$ 85	$ (99)