Condensed Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Condensed Consolidated Statements of Comprehensive Income
Net income (loss)	$ 285.0	$ 452.1
Other comprehensive income (loss), net:
Net unrealized gains (losses) on available-for-sale securities	(1,411.6)	1,104.3
Noncredit component of impairment losses on fixed maturities, available-for-sale		(2.5)
Net unrealized gains (losses) on derivative instruments	48.6	(4.5)
Foreign currency translation adjustment	(294.3)	37.9
Net unrecognized postretirement benefit obligation	11.0	11.5
Other comprehensive income (loss)	(1,646.3)	1,146.7
Comprehensive income (loss)	(1,361.3)	1,598.8
Comprehensive income (loss) attributable to noncontrolling interest	(13.1)	22.7
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	$ (1,348.2)	$ 1,576.1