Employee Retirement Benefits (Fair Value of Plan Assets) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	$ 563.1	$ 498.4	$ 423.2
Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	195.0	169.0
Short-term Investments | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	13.4	8.3
Short-term Investments | Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	0	12.9
Diversified Growth Funds | Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	74.1	0
US Large Cap Equity Securities | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	159.6	135.9
US Mid Cap Equity Securities | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	45.4	42.0
US Small Cap Equity Securities | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	36.2	31.6
International Larg Cap | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	100.7	109.3
International Emerging Markets | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	18.3	0
US Treasuries | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	59.8	67.5
Corporate Bonds | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	106.0	83.8
Government Bonds | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	5.9	4.4
Municipal Bonds | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	11.4	9.1
Real Estate Bonds | U.S. Plan
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	6.4	6.5
U.K. Equities | Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	24.3	66.1
Overseas Equities | Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	29.3	67.1
UK Conventional Gilts | Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	0	6.5
Foreign Overseas Corporate Bond Securities | Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	20.3	5.3
Global Treasury Bonds | Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	0	9.3
Index-Linked Gilts-Stocks | Pension Benefits - U.K.
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Total fair value of pension plan assets	$ 47.0	$ 1.8