Segment Information (Financial Information by Segment) (Details) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019 USD ($)	Jun. 30, 2018 USD ($)	Jun. 30, 2019 USD ($) reportable_segment	Jun. 30, 2018 USD ($)	Dec. 31, 2018 USD ($)
Segment Reporting Information [Line Items]
Number of reportable segments | reportable_segment			4
Revenues
Net earned premiums	$ 2,032.7	$ 1,338.3	$ 3,937.1	$ 2,463.2
Fees and other income	336.1	354.2	664.4	718.7
Net investment income	154.2	135.6	320.5	265.8
Net realized gains on investments	17.8	(11.4)	46.6	(10.9)
Amortization of deferred gains on disposal of businesses	4.7	15.0	12.5	33.5
Total revenues	2,545.5	1,831.7	4,981.1	3,470.3
Benefits, losses and expenses
Policyholder benefits	687.0	490.6	1,301.7	905.2
Amortization of deferred acquisition costs and value of business acquired	815.8	463.2	1,593.1	809.6
Underwriting, general and administrative expenses	832.9	773.6	1,633.0	1,493.2
Interest expense	26.5	26.0	53.0	47.5
Total benefits, losses and expenses	2,362.2	1,753.4	4,580.8	3,255.5
Income before provision for income taxes	183.3	78.3	400.3	214.8
Provision (benefit) for income taxes	40.7	11.3	89.1	41.8
Net income	142.6	67.0	311.2	173.0
Less: Net loss (income) attributable to non-controlling interests	1.5	0.0	(1.4)	0.0
Net income attributable to stockholders	144.1	67.0	309.8	173.0
Less: Preferred stock dividends	(4.6)	(4.8)	(9.3)	(4.8)
Net income attributable to common stockholders	139.5	62.2	300.5	168.2
Segment assets	43,139.5		43,139.5		$ 41,089.3
Other intangible asset impairment			14.6	0.0
Global Housing
Revenues
Net earned premiums	471.8	449.7	931.9	886.1
Fees and other income	38.3	92.8	78.2	179.5
Net investment income	18.8	15.9	44.2	36.1
Net realized gains on investments	0.0	0.0	0.0	0.0
Amortization of deferred gains on disposal of businesses	0.0	0.0	0.0	0.0
Total revenues	528.9	558.4	1,054.3	1,101.7
Benefits, losses and expenses
Policyholder benefits	207.8	187.2	406.7	356.3
Amortization of deferred acquisition costs and value of business acquired	57.5	50.4	111.4	100.0
Underwriting, general and administrative expenses	173.3	229.3	354.0	464.2
Interest expense	0.0	0.0	0.0	0.0
Total benefits, losses and expenses	438.6	466.9	872.1	920.5
Income before provision for income taxes	90.3	91.5	182.2	181.2
Provision (benefit) for income taxes	18.8	18.9	38.0	37.4
Net income	71.5		144.2
Less: Net loss (income) attributable to non-controlling interests	0.0		0.0
Net income attributable to stockholders	71.5	72.6	144.2	143.8
Less: Preferred stock dividends	0.0	0.0	0.0	0.0
Net income attributable to common stockholders	71.5	72.6	144.2	143.8
Segment assets	4,029.6		4,029.6
Global Lifestyle
Revenues
Net earned premiums	1,545.5	874.3	2,974.0	1,547.9
Fees and other income	263.6	227.9	516.7	472.8
Net investment income	56.5	36.6	115.4	68.7
Net realized gains on investments	0.0	0.0	0.0	0.0
Amortization of deferred gains on disposal of businesses	0.0	0.0	0.0	0.0
Total revenues	1,865.6	1,138.8	3,606.1	2,089.4
Benefits, losses and expenses
Policyholder benefits	412.9	239.3	760.1	420.9
Amortization of deferred acquisition costs and value of business acquired	740.7	395.6	1,446.5	675.9
Underwriting, general and administrative expenses	570.2	419.6	1,126.0	835.4
Interest expense	0.0	0.0	0.0	0.0
Total benefits, losses and expenses	1,723.8	1,054.5	3,332.6	1,932.2
Income before provision for income taxes	141.8	84.3	273.5	157.2
Provision (benefit) for income taxes	32.5	16.2	63.6	33.3
Net income	109.3		209.9
Less: Net loss (income) attributable to non-controlling interests	0.0		0.0
Net income attributable to stockholders	109.3	68.1	209.9	123.9
Less: Preferred stock dividends	0.0	0.0	0.0	0.0
Net income attributable to common stockholders	109.3	68.1	209.9	123.9
Segment assets	22,113.9		22,113.9
Global Preneed
Revenues
Net earned premiums	15.4	14.2	31.2	28.8
Fees and other income	34.2	32.7	67.5	64.3
Net investment income	70.6	67.9	139.7	133.7
Net realized gains on investments	0.0	0.0	0.0	0.0
Amortization of deferred gains on disposal of businesses	0.0	0.0	0.0	0.0
Total revenues	120.2	114.8	238.4	226.8
Benefits, losses and expenses
Policyholder benefits	66.2	65.0	134.8	131.7
Amortization of deferred acquisition costs and value of business acquired	17.6	17.2	35.2	33.7
Underwriting, general and administrative expenses	14.7	13.8	31.6	30.0
Interest expense	0.0	0.0	0.0	0.0
Total benefits, losses and expenses	98.5	96.0	201.6	195.4
Income before provision for income taxes	21.7	18.8	36.8	31.4
Provision (benefit) for income taxes	4.8	4.1	8.1	6.9
Net income	16.9		28.7
Less: Net loss (income) attributable to non-controlling interests	0.0		0.0
Net income attributable to stockholders	16.9	14.7	28.7	24.5
Less: Preferred stock dividends	0.0	0.0	0.0	0.0
Net income attributable to common stockholders	16.9	14.7	28.7	24.5
Segment assets	7,264.6		7,264.6
Total Corporate and Other
Revenues
Net earned premiums	0.0	0.1	0.0	0.4
Fees and other income	0.0	0.8	2.0	2.1
Net investment income	8.3	15.2	21.2	27.3
Net realized gains on investments	17.8	(11.4)	46.6	(10.9)
Amortization of deferred gains on disposal of businesses	4.7	15.0	12.5	33.5
Total revenues	30.8	19.7	82.3	52.4
Benefits, losses and expenses
Policyholder benefits	0.1	(0.9)	0.1	(3.7)
Amortization of deferred acquisition costs and value of business acquired	0.0	0.0	0.0	0.0
Underwriting, general and administrative expenses	74.7	110.9	121.4	163.6
Interest expense	26.5	26.0	53.0	47.5
Total benefits, losses and expenses	101.3	136.0	174.5	207.4
Income before provision for income taxes	(70.5)	(116.3)	(92.2)	(155.0)
Provision (benefit) for income taxes	(15.4)	(27.9)	(20.6)	(35.8)
Net income	(55.1)		(71.6)
Less: Net loss (income) attributable to non-controlling interests	1.5		(1.4)
Net income attributable to stockholders	(53.6)	(88.4)	(73.0)	(119.2)
Less: Preferred stock dividends	(4.6)	(4.8)	(9.3)	(4.8)
Net income attributable to common stockholders	(58.2)	$ (93.2)	(82.3)	$ (124.0)
Segment assets	9,731.4		9,731.4
Green Tree Insurance Agency, Inc.
Benefits, losses and expenses
Other intangible asset impairment	$ 14.6		$ 14.6