Cash includes currency on hand as well as demand deposits with banks or financial institutions. It also includes other kinds of accounts that have the general characteristics of demand deposits in that the customer may deposit additional funds at any time and effectively may withdraw funds at any time without prior notice or penalty. Cash equivalents, excluding items classified as marketable securities, include short-term, highly liquid Investments that are both readily convertible to known amounts of cash, and so near their maturity that they present minimal risk of changes in value because of changes in interest rates. Generally, only investments with original maturities of three months or less qualify under that definition. Original maturity means original maturity to the entity holding the investment. For example, both a three-month US Treasury bill and a three-year Treasury note purchased three months from maturity qualify as cash equivalents. However, a Treasury note purchased three years ago does not become a cash equivalent when its remaining maturity is three months. Short-term investments, exclusive of cash equivalents, generally consist of marketable securities intended to be sold within one year (or the normal operating cycle if longer) and may include trading securities, available-for-sale securities, or held-to-maturity securities (if maturing within one year), as applicable.

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Related Party Transactions (Reinsurance Transactions - Narrative) (Details) - USD ($) $ in Millions		3 Months Ended			6 Months Ended	9 Months Ended
	Apr. 30, 2017	Sep. 30, 2017	Jun. 30, 2017	Sep. 30, 2016	Jun. 30, 2017	Sep. 30, 2017	Sep. 30, 2016	May 01, 2017	Jan. 01, 2017	Dec. 31, 2016
Reinsurance Disclosures [Abstract]
Embedded Derivative, Fair Value of Embedded Derivative Liability		$ 2,289				$ 2,289				$ 3,170
Embedded Derivative, Fair Value of Embedded Derivative Asset		164				164				360
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net		585		$ 531		1,036	$ (3,486)
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest		(122)		(786)		(1,187)	(2,322)
Deferred Policy Acquisition Costs and Present Value of Future Insurance Profits, Net		5,737				5,737				6,339
Premiums, reinsurance and other receivables		13,005				13,005				13,853
Liability for Future Policy Benefits		35,379				35,379				32,752
Policyholder Contract Deposits		36,571				36,571				36,579
Other liabilities relating to variable interest entities		4,916				4,916				5,445
Affiliated Entity \| Assumed guaranteed minimum benefits
Reinsurance Disclosures [Abstract]
Embedded Derivative, Fair Value of Embedded Derivative Liability		454				454				741
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net		21		32		159	(276)
Affiliated Entity \| Ceded guaranteed minimum benefits
Reinsurance Disclosures [Abstract]
Embedded Derivative, Fair Value of Embedded Derivative Asset		2				2				$ 171
Embedded Derivative, Gain (Loss) on Embedded Derivative, Net		$ (1)		$ (6)		(126)	$ 136
Affiliated Entity \| Life and Other [Member]
Reinsurance Disclosures [Abstract]
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest	$ 17
Cash, Cash Equivalents, and Short-term Investments								$ 214
Premiums, reinsurance and other receivables								$ 189
Affiliated Entity \| Affiliate Recapture Variable Annuities [Member]
Reinsurance Disclosures [Abstract]
Cash, Cash Equivalents, and Short-term Investments									$ 184
Liability for Future Policy Benefits									34
Policyholder Contract Deposits									219
Other liabilities relating to variable interest entities									68
Metropolitan Life Insurance Company [Member] \| Affiliated Entity \| MLUS Recapture GMIB [Member]
Reinsurance Disclosures [Abstract]
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest			$ 91		$ 89
Cash, Cash Equivalents, and Short-term Investments									568
Premiums, reinsurance and other receivables			$ 140		$ 140
Liability for Future Policy Benefits									106
Policyholder Contract Deposits									460
Brighthouse Life Insurance Company NY [Member] \| Affiliated Entity \| Affiliate Recapture Variable Annuities [Member]
Reinsurance Disclosures [Abstract]
Income (Loss) from Continuing Operations before Income Taxes, Noncontrolling Interest						$ 0
Cash, Cash Equivalents, and Short-term Investments									150
Liability for Future Policy Benefits									45
Policyholder Contract Deposits									168
Other liabilities relating to variable interest entities									$ 359