Employee Benefits (Details) (USD $) In Millions | 3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2011 | Sep. 30, 2010 | Sep. 30, 2011 | Sep. 30, 2010 | |
| Employee Benefits (Textuals) [Abstract] | ||||
| Contribution towards retirement plans | $ 21.8 | |||
| Expected contribution towards retirement plans | 6 | 6 | ||
Retirement Plans [Member] | ||||
| Components of net periodic cost for retirement plans and post-retirement plans | ||||
| Service cost | 16.7 | 15.2 | 50.2 | 45.8 |
| Interest cost | 24.9 | 23.5 | 74.5 | 70.4 |
| Expected return on plan assets | (31.8) | (27.9) | (95.5) | (83.6) |
| Amortization of prior service credit | (0.1) | (0.3) | (0.1) | |
| Amortization of actuarial (gain) loss | 7.7 | 3.7 | 23.0 | 11.1 |
| Net periodic benefit cost | 17.4 | 14.5 | 51.9 | 43.6 |
Post-Retirement Plans [Member] | ||||
| Components of net periodic cost for retirement plans and post-retirement plans | ||||
| Service cost | 0.6 | 0.7 | 2.0 | 1.9 |
| Interest cost | 1.2 | 1.8 | 4.6 | 5.5 |
| Amortization of prior service credit | (0.3) | (0.3) | (0.9) | (0.9) |
| Amortization of actuarial (gain) loss | (0.1) | |||
| Net periodic benefit cost | $ 1.4 | $ 2.2 | $ 5.7 | $ 6.5 |