Segment Information (Total Assets of Reportable Segments) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2014	Dec. 31, 2013
Segment Total Assets [Line Items]
Total assets	$ 40,541,581	$ 39,674,473
US Traditional Segment Reporting Information [Member]
Segment Total Assets [Line Items]
Total assets	13,326,226	13,285,423
US Non-Traditional Segment Reporting Information [Member]
Segment Total Assets [Line Items]
Total assets	11,743,411	11,716,908
Canada Segment Reporting Information [Member]
Segment Total Assets [Line Items]
Total assets	4,012,037	4,103,730
Europe And South Africa Segment Reporting Information [Member]
Segment Total Assets [Line Items]
Total assets	2,572,563	2,230,568
Asia Pacific Segment Reporting Information [Member]
Segment Total Assets [Line Items]
Total assets	3,657,850	3,597,456
Corporate And Other Segment Reporting Information [Member]
Segment Total Assets [Line Items]
Total assets	$ 5,229,494	$ 4,740,388