Consolidated Statements of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Revenues
Premiums and other considerations	$ 803.6	$ 694.7
Fees and other revenues	829.7	733.6
Net investment income (loss)	844.7	789.3
Net realized capital gains (losses), excluding impairment losses on available-for-sale securities	19.8	(26.4)
Net other-than-temporary impairment (losses) recoveries on available-for-sale securities	10.9	(44.7)
Other-than-temporary impairment losses on fixed maturities, available-for-sale reclassified to (from) other comprehensive income	(30.1)	20.2
Net impairment losses on available-for-sale securities	(19.2)	(24.5)
Net realized capital gains (losses)	0.6	(50.9)
Total revenues	2,478.6	2,166.7
Expenses
Benefits, claims and settlement expenses	1,227.5	1,094.5
Dividends to policyholders	45.7	48.3
Operating expenses	829.0	795.7
Total expenses	2,102.2	1,938.5
Income (loss) before income taxes	376.4	228.2
Income taxes (benefits)	52.3	38.2
Net income (loss)	324.1	190.0
Net income (loss) attributable to noncontrolling interest	22.2	3.5
Net income (loss) attributable to Principal Financial Group, Inc.	301.9	186.5
Preferred stock dividends	8.2	8.2
Net income (loss) available to common stockholders	$ 293.7	$ 178.3
Earnings per common share
Basic earnings per common share (in dollars per share)	$ 0.96	$ 0.61
Diluted earnings per common share (in dollars per share)	$ 0.95	$ 0.61