CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY - USD ($) $ in Millions	Total	Common shares and paid-in surplus	Retained earnings	AOCI, after tax	Total	Non-controlling interest	Total Equity	Foreign Currency Gain (Loss) [Member] Common shares and paid-in surplus	Foreign Currency Gain (Loss) [Member] Retained earnings	Foreign Currency Gain (Loss) [Member] AOCI, after tax	Foreign Currency Gain (Loss) [Member] Total	Foreign Currency Gain (Loss) [Member] Non-controlling interest	Foreign Currency Gain (Loss) [Member] Total Equity	Pension liability and other accumulated comprehensive items [Member] Common shares and paid-in surplus	Pension liability and other accumulated comprehensive items [Member] Retained earnings	Pension liability and other accumulated comprehensive items [Member] AOCI, after tax	Pension liability and other accumulated comprehensive items [Member] Total	Pension liability and other accumulated comprehensive items [Member] Non-controlling interest	Pension liability and other accumulated comprehensive items [Member] Total Equity
Balances at Dec. 31, 2013		$ 1,051.1	$ 2,801.8	$ 52.1	$ 3,905.0	$ 491.8	$ 4,396.8
Increase (Decrease) in Shareholders' Equity
Net income	$ 235.1	0.0	242.3	0.0	242.3	(7.2)	235.1
Net change in unrealized gains (losses) from investments in unconsolidated affiliates	59.5	0.0	0.0	59.5	59.5	0.0	59.5
Other Comprehensive Income (Loss), Net of Tax								$ 0.0	$ 0.0	$ (100.3)	$ (100.3)	$ (0.1)	$ (100.4)	$ 0.0	$ 0.0	$ 0.4	$ 0.4	$ 0.0	$ 0.4
Total comprehensive income (loss)	201.8	0.0	242.3	(40.4)	201.9	(7.3)	194.6
Dividends declared on common shares		0.0	(6.2)	0.0	(6.2)	0.0	(6.2)
Dividends to non-controlling interests	0.0	0.0	0.0	0.0	0.0	(26.0)	(26.0)
Repurchases and retirements of common shares		(29.6)	(77.3)	0.0	(106.9)	0.0	(106.9)
Issuances of common shares		2.9	0.0	0.0	2.9	0.0	2.9
Noncontrolling Interest, Period Increase (Decrease)		0.0	0.0	0.0	0.0	29.4	29.4
Amortization of restricted share awards		12.5	0.0	0.0	12.5	0.6	13.1
Balances at Sep. 30, 2014		1,036.9	2,960.6	11.7	4,009.2	488.5	4,497.7
Balances at Dec. 31, 2014	4,538.4	1,034.7	3,010.5	(49.5)	3,995.7	542.7	4,538.4
Increase (Decrease) in Shareholders' Equity
Net income	5.5	0.0	29.7	0.0	29.7	(24.2)	5.5
Net change in unrealized gains (losses) from investments in unconsolidated affiliates	(29.4)	0.0	0.0	(29.4)	(29.4)	0.0	(29.4)
Other Comprehensive Income (Loss), Net of Tax								$ 0.0	$ 0.0	$ (62.6)	$ (62.6)	$ 0.0	$ (62.6)	$ 0.0	$ 0.0	$ 0.7	$ 0.7	$ 0.1	$ 0.8
Total comprehensive income (loss)	(61.5)	0.0	29.7	(91.3)	(61.6)	(24.1)	(85.7)
Dividends declared on common shares		0.0	(6.0)	0.0	(6.0)	0.0	(6.0)
Dividends to non-controlling interests	9.1	0.0	0.0	0.0	0.0	(35.4)	(35.4)
Repurchases and retirements of common shares		(46.0)	(145.9)	0.0	(191.9)	0.0	(191.9)
Issuances of common shares		0.9	0.0	0.0	0.9	0.0	0.9
Noncontrolling Interest, Decrease from Redemptions or Purchase of Interests		0.0	0.0	0.0	0.0	(31.5)	(31.5)
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Additional Interest Issued to Parent		(2.2)	0.0	0.0	(2.2)	(2.7)	(4.9)
Noncontrolling Interest, Period Increase (Decrease)		0.0	0.0	0.0	0.0	12.1	12.1
Amortization of restricted share awards		10.6	0.0	0.0	10.6	(0.3)	10.3
Balances at Sep. 30, 2015	$ 4,206.3	$ 998.0	$ 2,888.3	$ (140.8)	$ 3,745.5	$ 460.8	$ 4,206.3