Dispositions - Separation of Brighthouse - Balance Sheet (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary	$ 0	$ 216,983
Cash and Cash Equivalents	0	5,226	$ 1,570	$ 1,603
Liabilities of disposed subsidiary	$ 0	202,707
Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		216,983
Cash and Cash Equivalents		5,226
Other Assets		709
Liabilities of disposed subsidiary		202,707
Deferred Tax Liabilities, Current		2,594
Other Liabilities, Current		5,119
Fixed maturity securities | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		61,326
Equity securities | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		300
Mortgage Loans | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		9,378
Policy loans | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		1,517
Real estate and real estate joint ventures | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		150
Other limited partnership interests | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		1,642
Short-term Investments | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		1,288
Other invested assets | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		3,881
Investments | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		79,482
Accrued investment income | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Cash and Cash Equivalents		680
Premiums, reinsurance and other receivables | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		10,636
Deferred policy acquisition costs and value of business acquired | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		7,207
Separate Account assets | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Assets of disposed subsidiary		113,043
Future policy benefits | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities of disposed subsidiary		33,270
Policyholder Account Balances | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities of disposed subsidiary		37,066
Other Policy-Related Balances | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities of disposed subsidiary		1,356
Policyholder dividends payable | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities of disposed subsidiary		12
Payables for collateral under securities loaned and other transactions | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities of disposed subsidiary		7,390
Long-term Debt | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities of disposed subsidiary		60
Secured Debt | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities of disposed subsidiary		2,797
Separate account liabilities | Brighthouse Financial, Inc [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liabilities of disposed subsidiary		$ 113,043