Consolidated Statements of Financial Position (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Assets
Fixed maturities, available-for-sale (2014 and 2013 include $278.2 million and $272.0 million related to consolidated variable interest entities)	$ 49,670.8	$ 48,757.1
Fixed maturities, trading (2014 and 2013 include $100.4 million and $110.4 million related to consolidated variable interest entities)	604.6	563.1
Equity securities, available-for-sale	123.0	110.5
Equity securities, trading (2014 and 2013 include $345.3 million and $327.2 million related to consolidated variable interest entities)	840.2	716.9
Mortgage loans	11,811.6	11,533.6
Real estate (2014 and 2013 include $284.9 million and $266.3 million related to consolidated variable interest entities)	1,344.6	1,271.6
Policy loans	829.2	859.7
Other investments (2014 and 2013 include $40.6 million and $68.1 million related to consolidated variable interest entities and $127.2 million and $142.9 million measured at fair value under the fair value option)	3,209.8	2,944.4
Total investments	68,433.8	66,756.9
Cash and cash equivalents	1,863.9	2,371.8
Accrued investment income	505.9	532.1
Premiums due and other receivables	1,213.0	1,241.0
Deferred acquisition costs	2,993.0	3,077.0
Property and equipment	590.2	500.7
Goodwill	1,007.4	1,100.3
Other intangibles	1,323.5	1,459.0
Separate account assets (2014 and 2013 include $34,655.4 million and $32,824.7 million related to consolidated variable interest entities)	140,072.8	130,018.4
Other assets	1,083.5	1,134.2
Total assets	219,087.0	208,191.4
Liabilities
Contractholder funds	34,726.7	35,958.3
Future policy benefits and claims	24,036.6	22,626.2
Other policyholder funds	812.7	758.9
Short-term debt	28.0	150.6
Long-term debt (2014 and 2013 include $82.3 million and $47.7 million related to consolidated variable interest entities)	2,531.2	2,601.4
Income taxes currently payable	11.5	5.2
Deferred income taxes	1,035.3	824.0
Separate account liabilities (2014 and 2013 include $34,655.4 million and $32,824.7 million related to consolidated variable interest entities)	140,072.8	130,018.4
Other liabilities (2014 and 2013 include $344.0 million and $362.4 million related to consolidated variable interest entities, of which $71.0 million and $104.9 million are measured at fair value under the fair value option)	5,542.2	5,224.2
Total liabilities	208,797.0	198,167.2
Redeemable noncontrolling interest	58.0	247.2
Stockholders' equity
Common stock, par value $.01 per share - 2,500.0 million shares authorized, 462.7 million and 459.3 million shares issued, and 293.9 million and 295.2 million shares outstanding in 2014 and 2013	4.6	4.6
Additional paid-in capital	9,945.5	9,798.9
Retained earnings (accumulated deficit)	6,114.1	5,405.4
Accumulated other comprehensive income (loss)	50.4	183.2
Treasury stock, at cost (168.8 million and 164.1 million shares in 2014 and 2013)	(5,930.7)	(5,708.0)
Total stockholders' equity attributable to Principal Financial Group, Inc.	10,184.0	9,684.2
Noncontrolling interest	48.0	92.8
Total stockholders' equity	10,232.0	9,777.0
Total liabilities and stockholders' equity	219,087.0	208,191.4
Series A
Stockholders' equity
Preferred stock, value	0	0
Total stockholders' equity	0	0
Series B
Stockholders' equity
Preferred stock, value	0.1	0.1
Total stockholders' equity	$ 0.1	$ 0.1