Condensed Consolidated Statement of Comprehensive Income (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Statement of Income and Comprehensive Income [Abstract]
Net income	$ 227.6	$ 129.4	$ 302.4	$ 228.7
Other Comprehensive Income (Loss), before Tax [Abstract]
Currency translation differences on investments in overseas subsidiaries	(115.9)	31.6	(16.1)	152.3
Change in accumulated other comprehensive income related to employee benefit plans	2.0	0.2	0.9	10.2
Change in accumulated other comprehensive income of equity method investments	1.0	(2.3)	3.0	(1.1)
Change in net unrealized gains on available-for-sale investments	(2.1)	(2.9)	3.4	(2.6)
Other comprehensive income, before tax	(115.0)	26.6	(8.8)	158.8
Other Comprehensive Income (Loss), Tax [Abstract]
Tax benefit (expense) on foreign currency translation adjustments	0.8	(0.8)	0.8	(0.8)
Tax benefit (expense) on comprehensive income related to employee benefit plans	(0.5)	(0.1)	(0.2)	(2.5)
Tax expense on change in net unrealized gains on available-for-sale investments	0.3	0.1	0.2	0.1
Total income tax expense related to items of other comprehensive income	0.6	(0.8)	0.8	(3.2)
Other comprehensive income, net of tax	(114.4)	25.8	(8.0)	155.6
Total comprehensive income	113.2	155.2	294.4	384.3
Comprehensive income attributable to noncontrolling interests in consolidated entities	(50.5)	56.6	70.0	125.2
Comprehensive income attributable to common shareholders		$ 211.8	$ 364.4	$ 509.5