Segment Information (Assets) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues	$ 2,318,600	$ 2,516,200	$ 2,225,100	$ 1,960,900	$ 2,013,800	$ 2,432,300	$ 2,072,300	$ 1,780,000	$ 9,020,807	$ 8,298,380	$ 7,562,534
Assets	23,286,038				17,673,527				23,286,038	17,673,527
Property Subject to or Available for Operating Lease, Net	12,908,336				10,105,409				12,908,336	10,105,409
Property, Plant and Equipment, Net	1,436,386				1,251,854				1,436,386	1,251,854
United States
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									6,313,400	5,413,300	4,993,700
Assets	18,136,700				12,730,600				18,136,700	12,730,600
Property Subject to or Available for Operating Lease, Net	10,221,300				7,621,200				10,221,300	7,621,200
Property, Plant and Equipment, Net	1,226,100				1,036,700				1,226,100	1,036,700
International
Revenues from External Customers and Long-Lived Assets [Line Items]
Revenues									2,707,400	2,885,100	2,568,800
Assets	5,149,300				4,942,900				5,149,300	4,942,900
Property Subject to or Available for Operating Lease, Net	2,687,000				2,484,200				2,687,000	2,484,200
Property, Plant and Equipment, Net	$ 210,300				$ 215,200				$ 210,300	$ 215,200