Investments (Changes in Net Unrealized Investment Gains (Losses)) (Details) $ in Millions	3 Months Ended
Mar. 31, 2020 USD ($)
Investments, Debt and Equity Securities [Abstract]
Unrealized investment gains (losses), beginning of period	$ 3,229
Unrealized investment gains (losses) during the period	(319)
Unrealized investment gains (losses) relating to: Future policy benefits	(734)
Unrealized investment gains (losses) relating to: DAC, VOBA and DSI	85
Unrealized investment gains (losses) relating to: Deferred income tax benefit (expense)	204
Unrealized investment gains (losses), end of period	2,465
Change in net unrealized investment gains (losses)	$ (764)

This item presents the increase (decrease) in net unrealized investment gains (losses) attributable to the Company.

No definition available.

Name:	bhl_ChangesInNetUnrealizedInvestmentGainsLossesAttributableToCompany
Namespace Prefix:	bhl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) related to DAC and VOBA.

+ References

No definition available.

+ Details

Name:	bhl_ChangesInNetUnrealizedInvestmentGainsLossesRelatedToDacAndVoba
Namespace Prefix:	bhl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) related to insurance liability gain (loss) recognition.

+ References

No definition available.

+ Details

Name:	bhl_ChangesInNetUnrealizedInvestmentGainsLossesRelatedToInsuranceLiabilityGainLossRecognition
Namespace Prefix:	bhl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item presents the increase (decrease) in net unrealized investment gains (losses) related to unrealized investment gains (losses) during the period.

+ References

No definition available.

+ Details

Name:	bhl_ChangesInNetUnrealizedInvestmentGainsLossesRelatedToUnrealizedInvestmentGainsLossesDuringPeriod
Namespace Prefix:	bhl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

This item represents the tax effects occurring during the period which are related to the net unrealized gain (loss) resulting from changes in the fair [carrying] value during the period of available-for-sale securities and from changes in certain insurance related assets and liabilities. Such tax affects would have been charged or credited directly to other comprehensive income or to related components of shareholders' equity.

+ References

No definition available.

+ Details

Name:	bhl_IncomeTaxExpenseOnChangeInUnrealizedGainOrLoss
Namespace Prefix:	bhl_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

This item presents net unrealized investment gains (losses) attributable to the Company.

+ References

No definition available.

+ Details

Name:	bhl_NetUnrealizedInvestmentGainsLossesIncludedInAccumulatedOtherComprehensiveIncomeLossAttributableToCompany
Namespace Prefix:	bhl_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- References

No definition available.

+ Details

Name:	us-gaap_InvestmentsDebtAndEquitySecuritiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration