Consolidated Statements of Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Consolidated Statements of Comprehensive Income
Net income (loss)	$ 1,444.1	$ 1,553.7	$ 2,324.5
Other comprehensive income (loss), net:
Net unrealized gains (losses) on available-for-sale securities	2,616.1	(1,529.6)	639.5
Noncredit component of impairment losses on fixed maturities, available-for-sale	3.0	26.4	31.2
Net unrealized gains (losses) on derivative instruments	(11.0)	16.0	(42.6)
Foreign currency translation adjustment	(78.7)	(287.6)	178.9
Net unrecognized postretirement benefit obligation	77.3	(60.9)	37.3
Other comprehensive income (loss)	2,606.7	(1,835.7)	844.3
Comprehensive income (loss)	4,050.8	(282.0)	3,168.8
Comprehensive income (loss) attributable to noncontrolling interest	53.6	2.7	17.7
Comprehensive income (loss) attributable to Principal Financial Group, Inc.	$ 3,997.2	$ (284.7)	$ 3,151.1