Equity (Dividend Restrictions) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Metropolitan Life Insurance Company
Statutory Accounting Practices [Line Items]
Dividends		$ 5,740
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 2,523	3,600
Non-Cash Extraordinary Dividend of NELICO		981
Non-Cash Extraordinary Dividend of GALIC		1,200
Metropolitan Life Insurance Company | Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			$ 3,075
American Life Insurance Company
Statutory Accounting Practices [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	2,200	0
American Life Insurance Company | Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			0
Metropolitan Property and Casualty Insurance Company
Statutory Accounting Practices [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	185	228
Metropolitan Property and Casualty Insurance Company | Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			125
Metropolitan Tower Life Insurance Company
Statutory Accounting Practices [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0	60
Metropolitan Tower Life Insurance Company | Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			73
New England Life Insurance Company
Statutory Accounting Practices [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	0	295
General American Life Insurance Company
Statutory Accounting Practices [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	1	0
General American Life Insurance Company | Scenario, Forecast
Statutory Accounting Practices [Line Items]
Permitted w/o Approval			$ 118
Brighthouse Life Insurance Company [Member]
Statutory Accounting Practices [Line Items]
Cash Dividends Paid to Parent Company by Consolidated Subsidiaries	$ 0	$ 261