Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Consolidated Statements of Comprehensive Income
Net income (loss)	$ 264.9	$ 319.2	$ 694.0	$ 643.3
Other comprehensive income (loss), net:
Net unrealized gains (losses) on available-for-sale securities	(306.4)	178.3	(249.3)	370.5
Noncredit component of impairment losses on fixed maturities, available-for-sale	3.4	20.4	16.9	37.9
Net unrealized gains (losses) on derivative instruments	(16.1)	4.1	11.7	13.1
Foreign currency translation adjustment	(42.5)	33.0	(175.1)	(12.6)
Net unrecognized postretirement benefit obligation	12.0	3.6	24.0	7.1
Other comprehensive income (loss)	(349.6)	239.4	(371.8)	416.0
Comprehensive income (loss)	(84.7)	558.6	322.2	1,059.3
Comprehensive income (loss) attributable to noncontrolling interest	8.9	6.4	9.3	26.6
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	$ (93.6)	$ 552.2	$ 312.9	$ 1,032.7