CONSOLIDATED STATEMENTS OF CHANGES IN EQUITY (USD $) In Millions, unless otherwise specified	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	94.9	0	95.5	0	95.5	(0.6)	94.9
Net change in unrealized gains from investments in unconsolidated affiliates	36.5	0	0	36.5	36.5	0	36.5
Other Comprehensive Income (Loss), Net of Tax								0	0	(7.9)	(7.9)	0	(7.9)	0	0	0.1	0.1	0	0.1
Total comprehensive income (loss)	124.2	0	95.5	28.7	124.2	(0.6)	123.6
Dividends declared on common shares		0	(6.2)	0	(6.2)	0	(6.2)
Dividends to non-controlling interests	0	0	0	0	0	(5.2)	(5.2)
Repurchases and retirements of common shares		(4.5)	(10.9)	0	(15.4)	0	(15.4)
Issuances of common shares		2.1	0	0	2.1	0	2.1
Net contributions from non-controlling interests		0	0	0	0	27.0	27.0
Amortization of restricted share awards		4.2	0	0	4.2	0.2	4.4
Balances at Mar. 31, 2014		1,052.9	2,880.2	80.8	4,013.9	513.2	4,527.1
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	77.0	0	84.3	0	84.3	(7.3)	77.0
Net change in unrealized gains from investments in unconsolidated affiliates	28.9	0	0	28.9	28.9	0	28.9
Other Comprehensive Income (Loss), Net of Tax								0	0	(87.8)	(87.8)	0	(87.8)	0	0	0.2	0.2	0	0.2
Total comprehensive income (loss)	25.6	0	84.3	(58.7)	25.6	(7.3)	18.3
Dividends declared on common shares		0	(6.0)	0	(6.0)	0	(6.0)
Dividends to non-controlling interests	0.7	0	0	0	0	(7.0)	(7.0)
Repurchases and retirements of common shares		(3.0)	(8.0)	0	(11.0)	0	(11.0)
Consolidation, Less than Wholly Owned Subsidiary, Parent Ownership Interest, Changes, Additional Interest Issued to Parent		4.6	0	0	4.6	(4.6)	0
Net contributions from non-controlling interests		0	0	0	0	5.2	5.2
Amortization of restricted share awards		2.4	0	0	2.4	(0.5)	1.9
Balances at Mar. 31, 2015	$ 4,539.8	$ 1,038.7	$ 3,080.8	$ (108.2)	$ 4,011.3	$ 528.5	$ 4,539.8