Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Consolidated Statements of Comprehensive Income
Net income (loss)	$ 392.1	$ 459.5	$ 844.2	$ 862.0
Other comprehensive income (loss), net:
Net unrealized gains (losses) on available-for-sale securities	984.9	(466.1)	2,089.2	(1,271.6)
Noncredit component of impairment losses on fixed maturities, available-for-sale	(0.3)	0.8	(2.8)	10.1
Net unrealized gains (losses) on derivative instruments	1.6	20.3	(2.9)	5.9
Foreign currency translation adjustment	28.9	(236.1)	66.8	(170.3)
Net unrecognized postretirement benefit obligation	57.2	8.8	68.7	17.5
Other comprehensive income (loss)	1,072.3	(672.3)	2,219.0	(1,408.4)
Comprehensive income (loss)	1,464.4	(212.8)	3,063.2	(546.4)
Comprehensive income (loss) attributable to noncontrolling interest	11.5	(0.8)	34.2	5.5
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	$ 1,452.9	$ (212.0)	$ 3,029.0	$ (551.9)