Fair Value Measurements (Narrative) (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Carrying value and fair value of long-term obligations, including current portion	$ 8,753,376,000	$ 7,236,308,000
Impairment charges to write down certain assets to net realizable value	21,500,000	9,000,000	12,200,000
Assets held and used, original carrying value	5,379,200,000	4,280,800,000
Assets Held And Used Long Lived, Net Realizable Value	5,357,700,000	4,271,800,000
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, Low	0
Business Combination, Contingent Consideration Arrangements, Range of Outcomes, Value, High	43,600,000
Estimate of Fair Value, Fair Value Disclosure [Member]
Carrying value and fair value of long-term obligations, including current portion	9,359,575,000	7,500,000,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 1 [Member]
Carrying value and fair value of long-term obligations, including current portion	4,900,000,000	3,800,000,000
Estimate of Fair Value, Fair Value Disclosure [Member] | Fair Value, Inputs, Level 2 [Member]
Carrying value and fair value of long-term obligations, including current portion	$ 4,500,000,000	$ 3,700,000,000