Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Condensed Consolidated Statements of Comprehensive Income
Net income (loss)	$ 416.1	$ 392.1	$ 701.1	$ 844.2
Other comprehensive income (loss), net:
Net unrealized gains (losses) on available-for-sale securities	2,037.7	984.9	626.1	2,089.2
Noncredit component of impairment losses on fixed maturities, available-for-sale		(0.3)		(2.8)
Net unrealized gains (losses) on derivative instruments	(16.4)	1.6	32.2	(2.9)
Foreign currency translation adjustment	16.4	28.9	(277.9)	66.8
Net unrecognized postretirement benefit obligation	10.4	57.2	21.4	68.7
Other comprehensive income (loss)	2,048.1	1,072.3	401.8	2,219.0
Comprehensive income (loss)	2,464.2	1,464.4	1,102.9	3,063.2
Comprehensive income (loss) attributable to noncontrolling interest	16.0	11.5	2.9	34.2
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	$ 2,448.2	$ 1,452.9	$ 1,100.0	$ 3,029.0