Leases (Details 1) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011
Minimum Future Receipts
2012, Finance Leases	$ 38.0
2013, Finance Leases	38.0
2014, Finance Leases	36.9
2015, Finance Leases	33.2
2016, Finance Leases	28.9
Years thereafter, Finance Leases	166.4
Total, Finance Leases	341.4
2012, Operating Leases	745.5
2013, Operating Leases	544.9
2014, Operating Leases	385.2
2015, Operating Leases	290.0
2016, Operating Leases	188.8
Years thereafter, Operating Leases	362.1
Total, Operating Leases	2,516.5
2012, Leveraged Leases	18.1
2013, Leveraged Leases	0.3
2014, Leveraged Leases	0.4
2015, Leveraged Leases	0.3
2016, Leveraged Leases	0
Years thereafter, Leveraged Leases	79.3
Total, Leveraged Leases	98.4
2012, Total	801.6
2013, Total	583.2
2014, Total	422.5
2015, Total	323.5
2016, Total	217.7
Years thereafter, Total	607.8
Total	$ 2,956.3