Pension and Other Post Retirement Plans (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
OCI Amortization next 12 months	$ 12.2
U.S. qualified pension plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	42.5	41.9
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Total Recognized in OCI (Income) loss	(221.5)	(149.5)
Assumptions used to determine benefit obligations
Discount rate	4.69%	4.69%
U.S. qualified pension plan [Member] | Annual Expense [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Interest cost	42.5	41.9	39.5
Expected return on plan assets	(71.6)	(63.8)	(61.0)
Amortization of net (gain)/loss	5.7
Net periodic pension income	(23.4)	(21.9)	(21.5)
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Total Recognized in OCI (Income) loss	72.0	73.3	23.3
Total Recognized in net periodic benefit cost and OCI	(48.6)	(51.4)	(1.8)
Assumptions used to determine benefit obligations
Discount rate	4.69%	5.67%	6.15%
Expected return on plan assets	7.00%	7.00%	7.50%
U.K. pension plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	7.4	6.0
Interest cost	2.8	2.5
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Total Recognized in OCI (Income) loss	8.9	3.3
OCI Amortization next 12 months	(0.1)
Assumptions used to determine benefit obligations
Discount rate	4.70%	4.80%
Rate of compensation increase	3.10%	3.20%
U.K. pension plan [Member] | Annual Expense [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	7.4	6.0	5.8
Interest cost	2.8	2.5	2.1
Expected return on plan assets	(3.7)	(3.3)	(2.7)
Amortization of net (gain)/loss		(0.3)	(0.3)
Net periodic pension income	6.5	4.9	4.9
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Total Recognized in OCI (Income) loss	(4.9)	5.9	(1.1)
Total Recognized in net periodic benefit cost and OCI	(1.6)	(10.8)	(3.8)
Assumptions used to determine benefit obligations
Discount rate	4.80%	5.30%	5.70%
Expected return on plan assets	5.80%	6.10%	6.50%
Rate of compensation increase	3.20%	3.55%	4.20%
Postretirement Medical Plan [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	3.3	3.0
Interest cost	3.5	3.7
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Total Recognized in OCI (Income) loss	(4.4)	(20.4)
Assumptions used to determine benefit obligations
Discount rate	2.94%	4.23%
Medical Assumptions
Trend assumed for the year	8.50%	8.97%
Ultimate trend rate	4.50%	4.50%
Year the ultimate trend rate is reached	2030	2030
Postretirement Medical Plan [Member] | Annual Expense [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost	3.3	3.0	2.9
Interest cost	3.5	3.7	3.9
Amortization of net (gain)/loss	1.2	0.7	0.9
Net periodic pension income	8.0	7.4	7.7
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Total Recognized in OCI (Income) loss	(15.9)	4.6	2.4
Total Recognized in net periodic benefit cost and OCI	$ 7.9	$ (12.0)	$ (10.1)
Assumptions used to determine benefit obligations
Discount rate	4.23%	5.33%	5.89%
Medical Assumptions
Trend assumed for the year	8.97%	9.47%	10.00%
Ultimate trend rate	4.50%	4.50%	4.50%
Year the ultimate trend rate is reached	2030	2030	2030