Reclassifications from Accumulated Other Comprehensive Income - Schedule of Accumulated Other Comprehensive Income Reclassification (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Available for sale securities:
(Loss)/income from operations before income tax	$ (263.0)	$ 100.5	$ (86.7)	$ 283.6
General, administrative and corporate expenses	110.9	125.0	352.1	361.2
Income tax expense	9.2	(4.9)	5.2	(8.7)
Net (loss)/income	(253.8)	95.6	(81.5)	274.9
Reclassification out of AOCI
Available for sale securities:
Net (loss)/income	1.8	2.4	4.3	4.6
Reclassification out of AOCI \| Available for sale securities
Available for sale securities:
Realized gains on sale of securities	2.6	5.3	8.2	14.8
Realized (losses) on sale of securities	(1.6)	(0.9)	(5.4)	(5.1)
(Loss)/income from operations before income tax	1.0	4.4	2.8	9.7
Income tax expense	(0.2)	0.0	(0.4)	(0.6)
Net (loss)/income	0.8	4.4	2.4	9.1
Reclassification out of AOCI \| Realized derivatives
Available for sale securities:
General, administrative and corporate expenses	1.2	(3.1)	2.4	(5.6)
Income tax expense	(0.2)	1.1	(0.5)	1.1
Net (loss)/income	$ 1.0	$ (2.0)	$ 1.9	$ (4.5)

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This item represents the gross profit realized on the sale of debt or equity securities categorized neither as held-to-maturity nor trading securities.

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Amount of income (loss) from continuing operations before deduction of income tax expense (benefit) and income (loss) attributable to noncontrolling interest, and addition of income (loss) from equity method investments.

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The aggregate total costs related to selling a firm's product and services, as well as all other general and administrative expenses. Direct selling expenses (for example, credit, warranty, and advertising) are expenses that can be directly linked to the sale of specific products. Indirect selling expenses are expenses that cannot be directly linked to the sale of specific products, for example telephone expenses, Internet, and postal charges. General and administrative expenses include salaries of non-sales personnel, rent, utilities, communication, etc.

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