Retirement Benefits - Information comparing plan asssets to obligations (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
US Plans [Member]
Pension plans with an accumulated benefit obligation in excess of plan assets [Abstract]
Fair value of plan assets	$ 756.3	$ 685.4
Accumulated benefit obligation	1,031.3	990.7
Projected benefit obligation	1,031.3	990.7
Non-US Plans [Member]
Pension plans with an accumulated benefit obligation in excess of plan assets [Abstract]
Fair value of plan assets	137.2	117.5
Accumulated benefit obligation	223.2	179.8
Projected benefit obligation	268.4	206.4
Pension plan [Member]
Pension plans with an accumulated benefit obligation in excess of plan assets [Abstract]
Fair value of plan assets	893.5	802.9
Accumulated benefit obligation	1,254.5	1,170.5
Projected benefit obligation	$ 1,299.7	$ 1,197.1

If aggregate disclosures are presented, the aggregate pension accumulated benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

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If aggregate disclosures are presented, the aggregate fair value of plan assets for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References+ Details

- Definition

If aggregate disclosures are presented, the aggregate projected benefit obligation for pension plans with accumulated benefit obligations in excess of plan assets as of the measurement date of each statement of financial position presented.

+ References+ Details