Lease and Concession Agreements (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Lease and Concession Agreements
Rents paid for vehicles leased	$ 79.8	$ 96.1	$ 78.2
Revenue earning equipment, office and computer equipment
Lease and Concession Agreements
Rents paid for vehicles leased	92.0	106.2	88.6
Minimum obligations under existing agreements
2013	56.6
2014	25.2
2015	6.7
2016	2.1
2017	0
After 2017	0
Revenue earning equipment
Lease and Concession Agreements
Rents paid for vehicles leased	79.8	96.1	78.2
Office and computer equipment
Lease and Concession Agreements
Rents paid for vehicles leased	12.2	10.1	10.4
Concession agreements and real estate leases
Concession fees:
Total	714.9	691.1	664.6
Minimum obligations under existing agreements
Minimum future sublease rental inflows reduced from future minimum rent payments	(21.2)
Concession agreements and real estate leases | Maximum
Minimum obligations under existing agreements
Lease period of premises under operating leases	25 years
Rents
Lease and Concession Agreements
Rents paid for vehicles leased	135.9	130.6	133.9
Concession fees:
Sublease income that reduced rent expense	5.0	5.0	4.5
Minimum obligations under existing agreements
2013	157.3
2014	128.7
2015	99.3
2016	74.7
2017	50.4
After 2017	194.1
Concessions
Concession fees:
Minimum fixed obligations	249.6	248.7	252.0
Additional amounts, based on revenues	329.4	311.8	278.7
Minimum obligations under existing agreements
2013	390.3
2014	279.4
2015	192.8
2016	141.4
2017	91.3
After 2017	$ 509.7