Segment Information (Operating Results) (Details) - USD ($) $ in Millions	3 Months Ended				6 Months Ended
	Jun. 30, 2020	Mar. 31, 2020	Jun. 30, 2019	Mar. 31, 2019	Jun. 30, 2020	Jun. 30, 2019
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	$ (2,522)		$ 469		$ 3,730	$ (484)
Provision for income tax expense (benefit)	(531)		85		762	(133)
Post-tax adjusted earnings	(1,991)	$ 4,959	384	$ (735)	2,968	(351)
Less: Net income (loss) attributable to noncontrolling interests	0		0		2	2
Less: Preferred stock dividends	7		7		14	7
Net investment gains (losses)	(34)		63		(53)	52
Net derivative gains (losses)	(2,653)		149		4,249	(1,154)
Other adjustments to net income (loss)	93		96		195	188
Net income (loss) available to Brighthouse Financial, Inc.’s common shareholders	(1,998)		377		2,952	(360)
Annuities
Segment Reporting Information [Line Items]
Interest revenue	405		470		865	891
Interest expense	0		0		0	0
Life
Segment Reporting Information [Line Items]
Interest revenue	69		116		185	213
Interest expense	0		0		0	0
Run-off
Segment Reporting Information [Line Items]
Interest revenue	166		339		490	615
Interest expense	0		0		0	0
Corporate & Other
Segment Reporting Information [Line Items]
Interest revenue	16		17		36	34
Interest expense	45		48		92	95
Operating Segments
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	21		312		274	586
Provision for income tax expense (benefit)	3		51		36	91
Post-tax adjusted earnings	18		261		238	495
Less: Net income (loss) attributable to noncontrolling interests	0		0		2	2
Less: Preferred stock dividends	7		7		14	7
Adjusted earnings	11		254		222	486
Operating Segments | Annuities
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	205		323		594	684
Provision for income tax expense (benefit)	34		58		107	124
Post-tax adjusted earnings	171		265		487	560
Less: Net income (loss) attributable to noncontrolling interests	0		0		0	0
Less: Preferred stock dividends	0		0		0	0
Adjusted earnings	171		265		487	560
Operating Segments | Life
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	60		72		73	103
Provision for income tax expense (benefit)	12		14		14	20
Post-tax adjusted earnings	48		58		59	83
Less: Net income (loss) attributable to noncontrolling interests	0		0		0	0
Less: Preferred stock dividends	0		0		0	0
Adjusted earnings	48		58		59	83
Operating Segments | Run-off
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(146)		2		(236)	(44)
Provision for income tax expense (benefit)	(31)		0		(51)	(10)
Post-tax adjusted earnings	(115)		2		(185)	(34)
Less: Net income (loss) attributable to noncontrolling interests	0		0		0	0
Less: Preferred stock dividends	0		0		0	0
Adjusted earnings	(115)		2		(185)	(34)
Operating Segments | Corporate & Other
Segment Reporting Information [Line Items]
Pre-tax adjusted earnings	(98)		(85)		(157)	(157)
Provision for income tax expense (benefit)	(12)		(21)		(34)	(43)
Post-tax adjusted earnings	(86)		(64)		(123)	(114)
Less: Net income (loss) attributable to noncontrolling interests	0		0		2	2
Less: Preferred stock dividends	7		7		14	7
Adjusted earnings	(93)		(71)		(139)	(123)
Segment Reconciling Items
Segment Reporting Information [Line Items]
Provision for income tax expense (benefit)	534		(34)		(726)	224
Net investment gains (losses)	(34)		63		(53)	52
Net derivative gains (losses)	(2,653)		149		4,249	(1,154)
Other adjustments to net income (loss)	$ 144		$ (55)		$ (740)	$ 32