Employee Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Sep. 30, 2012
Defined Pension Benefit Plans
Employee benefit plans
Company contributions			$ 35.8
Components of net periodic benefit cost
Service cost	4.0	5.6
Interest cost	4.0	4.1
Expected return on plan assets	(4.1)	(3.9)
Amortization of prior service cost	0.4	0.6
Curtailment	0.9	0
Amortization of net actuarial loss	1.1	1.8
Net periodic benefit cost	6.3	8.2
Defined Pension Benefit Plans | Minimum
Employee benefit plans
Defined benefit pension plans estimated future employer contributions in fiscal year	10.0
Defined Pension Benefit Plans | Maximum
Employee benefit plans
Defined benefit pension plans estimated future employer contributions in fiscal year	15.0
Other Post-employment Benfit Plans
Employee benefit plans
Company contributions	0.4	0.3
Defined benefit pension plans estimated future employer contributions in fiscal year	1.1
Components of net periodic benefit cost
Service cost	2.0	1.8
Interest cost	0.8	0.9
Amortization of prior service cost	(0.1)	0
Amortization of net actuarial loss	0.3	0.3
Net periodic benefit cost	$ 3.0	$ 3.0