Segment Information (Details 2) (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
Financial information with respect to entity's operations by geographic area
Operating revenues and Earnings (losses) from unconsolidated affiliates from continuing operations	$ 1,596,807	$ 1,666,892	$ 1,602,797	$ 1,821,757	$ 1,731,979	$ 1,642,227	$ 1,352,950	$ 1,389,842	$ 6,688,253	$ 6,116,998	$ 4,167,750
Property, plant and equipment, net	8,712,088				8,629,946				8,712,088	8,629,946	7,815,419
Goodwill	472,326				501,258				472,326	501,258	494,372
U.S.
Financial information with respect to entity's operations by geographic area
Operating revenues and Earnings (losses) from unconsolidated affiliates from continuing operations									4,759,534	4,329,079	2,612,954
Property, plant and equipment, net	5,179,578				4,974,239				5,179,578	4,974,239	4,447,388
Goodwill	456,463				466,794				456,463	466,794	459,560
Outside the U.S.
Financial information with respect to entity's operations by geographic area
Operating revenues and Earnings (losses) from unconsolidated affiliates from continuing operations									1,928,719	1,787,919	1,554,796
Property, plant and equipment, net	3,532,510				3,655,707				3,532,510	3,655,707	3,368,031
Goodwill	$ 15,863				$ 34,464				$ 15,863	$ 34,464	$ 34,812