Consolidated Statements of Financial Position - USD ($) $ in Millions	Jun. 30, 2018	Dec. 31, 2017
Assets
Fixed maturities, available-for-sale (2018 and 2017 include $242.7 million and $268.0 million related to consolidated variable interest entities)	$ 59,311.7	$ 59,388.4
Fixed maturities, trading	688.1	566.0
Equity securities (2018 and 2017 include $791.3 million and $811.4 million related to consolidated variable interest entities)	1,869.3	1,866.6
Mortgage loans	14,367.9	14,150.5
Real estate (2018 and 2017 include $334.6 million and $370.3 million related to consolidated variable interest entities)	1,728.9	1,736.7
Policy loans	804.0	808.3
Other investments (2018 and 2017 include $205.2 million and $139.8 million related to consolidated variable interest entities and $21.1 million and $61.0 million measured at fair value under the fair value option)	3,634.9	3,586.2
Total investments	82,404.8	82,102.7
Cash and cash equivalents	2,342.0	2,470.8
Accrued investment income	627.8	610.6
Premiums due and other receivables	1,455.6	1,469.8
Deferred acquisition costs	3,574.4	3,540.7
Property and equipment	762.9	759.5
Goodwill	1,103.2	1,068.8
Other intangibles	1,355.4	1,314.7
Separate account assets (2018 and 2017 include $39,407.5 million and $41,540.8 million related to consolidated variable interest entities)	156,989.0	159,272.7
Other assets	1,488.9	1,330.9
Total assets	252,104.0	253,941.2
Liabilities
Contractholder funds (2018 and 2017 include $387.3 million and $380.6 million related to consolidated variable interest entities)	39,128.7	38,082.5
Future policy benefits and claims	33,390.7	33,019.3
Other policyholder funds	849.7	922.3
Short-term debt	64.5	39.5
Long-term debt (2018 and 2017 include $37.1 million and $2.8 million related to consolidated variable interest entities)	3,219.9	3,178.4
Income taxes currently payable	19.8	16.7
Deferred income taxes	887.9	1,092.5
Separate account liabilities (2018 and 2017 include $39,407.5 million and $41,540.8 million related to consolidated variable interest entities)	156,989.0	159,272.7
Other liabilities (2018 and 2017 include $259.1 million and $270.2 million related to consolidated variable interest entities)	5,708.4	5,294.1
Total liabilities	240,258.6	240,918.0
Redeemable noncontrolling interest (2018 and 2017 include $66.3 million and $52.4 million related to consolidated variable interest entities)	138.9	101.3
Stockholders' equity
Common stock, par value $.01 per share - 2,500.0 million shares authorized, 476.3 million and 474.1 million shares issued, and 284.6 million and 289.0 million shares outstanding in 2018 and 2017	4.8	4.7
Additional paid-in capital	9,993.6	9,925.2
Retained earnings (accumulated deficit)	9,904.3	9,482.9
Accumulated other comprehensive income (loss)	(1,137.9)	165.5
Treasury stock, at cost (191.7 million and 185.1 million shares in 2018 and 2017)	(7,125.5)	(6,729.0)
Total stockholders' equity attributable to Principal Financial Group, Inc.	11,639.3	12,849.3
Noncontrolling interest	67.2	72.6
Total stockholders' equity	11,706.5	12,921.9
Total liabilities and stockholders' equity	$ 252,104.0	$ 253,941.2