Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Revenues
Premiums	$ 1,160.9	$ 1,150.1	$ 3,457.7	$ 3,566.9
Net investment income	67.8	68.3	205.2	209.1
Net realized investment gains (losses):
Net realized gains from sales and other	4.3	12.2	31.0	38.8
Net other-than-temporary impairment losses on investments recognized in earnings	(0.1)	(4.2)	(26.0)	(8.8)
Total net realized investment gains	4.2	8.0	5.0	30.0
Fees and other income	8.3	7.1	22.9	23.3
Total revenues	1,241.2	1,233.5	3,690.8	3,829.3
Losses and expenses
Losses and loss adjustment expenses	692.0	690.7	2,121.3	2,208.7
Amortization of deferred acquisition costs	257.9	259.0	771.4	781.6
Interest expense	12.5	14.8	42.8	45.9
Gain on disposal of U.K. motor business	(0.1)		(1.3)	(37.7)
Net loss from repayment of debt		5.6	86.1	24.1
Other operating expenses	154.8	153.0	445.4	466.7
Total losses and expenses	1,117.1	1,123.1	3,465.7	3,489.3
Income before income taxes	124.1	110.4	225.1	340.0
Income tax expense (benefit):
Current	8.0	11.8	47.9	46.7
Deferred	27.8	21.4	8.9	40.3
Total income tax expense	35.8	33.2	56.8	87.0
Income from continuing operations	88.3	77.2	168.3	253.0
Net gain from discontinued operations (net of tax (expense) benefit of $(0.1) and $0.3 for the three months ended September 30, 2016 and September 30, 2015 and $2.1 and $0.5 for the nine months ended September 30, 2016 and September 30, 2015, respectively)	0.1	1.1	0.3	0.9
Net income	$ 88.4	$ 78.3	$ 168.6	$ 253.9
Basic:
Income from continuing operations	$ 2.07	$ 1.75	$ 3.93	$ 5.73
Net gain from discontinued operations		0.03	0.01	0.02
Net income per share	$ 2.07	$ 1.78	$ 3.94	$ 5.75
Weighted average shares outstanding	42.7	44.0	42.8	44.1
Diluted:
Income from continuing operations	$ 2.06	$ 1.72	$ 3.89	$ 5.62
Net gain from discontinued operations		0.02		0.02
Net income per share	$ 2.06	$ 1.74	$ 3.89	$ 5.64
Weighted average shares outstanding	43.0	44.9	43.3	45.0