Retirement Benefits - Obligations and Funded Status (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
US Plans [Member]
Changes in the benefit obligation [Roll Forward]
Service cost	$ 0	$ 0	$ 0	$ 0
Interest cost	10.6	11.0	31.7	33.0
Non-US Plans [Member]
Changes in the benefit obligation [Roll Forward]
Service cost	3.7	2.8	11.1	8.2
Interest cost	4.7	5.0	14.3	13.9
UMWA Plans Postretirement Medical [Member]
Changes in the benefit obligation [Roll Forward]
Service cost	0	0	0	0
Interest cost	4.9	5.6	14.8	16.8
Pension plan [Member]
Changes in the benefit obligation [Roll Forward]
Service cost	3.7	2.8	11.1	8.2
Interest cost	15.3	16.0	46.0	46.9
Retirement benefits other than pension [Member]
Changes in the benefit obligation [Roll Forward]
Service cost	0	0.2	0.2	0.3
Interest cost	$ 5.4	$ 6.3	$ 16.3	$ 19.0