Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Assets
Amortized cost of fixed maturity securities available-for-sale	$ 286,069	$ 271,676
Cost of equity securities available-for-sale	2,140	2,464
Fair value option and trading securities relating to variable interest entities	16,745	13,923
Mortgage loans valuation allowances	314	304
Mortgage Loans on Real Estate	68,731	65,167
Real estate held-for-sale	25	59
Other limited partnership interests relating to variable interest entities	5,708	5,136
Other invested assets relating to variable interest entities	17,263	19,303
Cash and cash equivalents relating to variable interest entities	12,701	12,651
Premiums, reinsurance and other receivables relating to variable interest entities	18,423	15,445
Other assets relating to variable interest entities	8,167	7,058
Liabilities
Long-term debt, at estimated fair value, relating to variable interest entities	15,686	16,441
Other liabilities relating to variable interest entities	$ 23,982	$ 23,735
MetLife, Inc.’s stockholders’ equity:
Preferred stock, par value	$ 0.01	$ 0.01
Preferred stock, aggregate liquidation preference	2,100	2,100
Common stock, par value	$ 0.01	$ 0.01
Common stock, shares authorized	3,000,000,000	3,000,000,000
Common stock, shares issued	1,168,710,101	1,164,029,985
Common stock, shares outstanding	1,043,588,396	1,095,519,005
Treasury stock, shares	125,121,705	68,510,980
Residential mortgage loans - FVO
Assets
Mortgage Loans on Real Estate	$ 520	$ 566
Variable interest entities
Assets
Fair value option and trading securities relating to variable interest entities	6	8
Other limited partnership interests relating to variable interest entities	0	14
Other invested assets relating to variable interest entities	125	31
Cash and cash equivalents relating to variable interest entities	12	1
Premiums, reinsurance and other receivables relating to variable interest entities	3	2
Other assets relating to variable interest entities	2	3
Liabilities
Long-term debt, at estimated fair value, relating to variable interest entities	6	12
Other liabilities relating to variable interest entities	$ 3	$ 0