Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Condensed Consolidated Statements of Comprehensive Income
Net income (loss)	$ 364.3	$ 235.9	$ 1,252.2	$ 937.0
Other comprehensive income (loss), net:
Net unrealized gains (losses) on available-for-sale securities	(23.6)	226.7	(606.1)	852.8
Net unrealized gains (losses) on derivative instruments	20.7	(25.1)	32.4	7.1
Foreign currency translation adjustment	(193.3)	94.3	(214.1)	(183.6)
Net unrecognized postretirement benefit obligation	9.3	10.5	21.2	31.9
Other comprehensive income (loss)	(186.9)	306.4	(766.6)	708.2
Comprehensive income (loss)	177.4	542.3	485.6	1,645.2
Comprehensive income (loss) attributable to noncontrolling interest	2.1	9.9	10.7	12.8
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	$ 175.3	$ 532.4	$ 474.9	$ 1,632.4