Guarantor Condensed Consolidating Financial Statements (Impact of Revision - Income Statement) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	$ 4,092.2	$ 3,487.7	$ 2,627.3
Increase/(decrease) in operating expenses	3,194.1	2,897.8	2,143.0
Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	1,299.5	1,031.6	549.7
Increase/(decrease) in operating expenses	798.7	742.4	432.1
Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	2,996.1	2,636.4	2,145.9
Increase/(decrease) in operating expenses	2,584.2	2,320.5	1,769.6
Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	0	0	4.7
Increase/(decrease) in operating expenses	0	0	1.4
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	0	0	0
Increase/(decrease) in operating expenses	14.6	15.2	12.9
Adjustments [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	(203.4)	(180.3)	(73.0)
Increase/(decrease) in operating expenses	(203.4)	(180.3)	(73.0)
Consolidated [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	4,092.2	3,487.7	2,627.3
Increase/(decrease) in operating expenses	3,194.1	2,897.8	2,143.0
Revision Adjustment [Member] | Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	0	0	0
Increase/(decrease) in operating expenses	0	0	0
Revision Adjustment [Member] | Non-Guarantors [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	203.4	180.3	68.3
Increase/(decrease) in operating expenses	203.4	180.3	68.3
Revision Adjustment [Member] | Issuer [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	0	0	4.7
Increase/(decrease) in operating expenses	0	0	4.7
Revision Adjustment [Member] | Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	0	0	0
Increase/(decrease) in operating expenses	0	0	0
Revision Adjustment [Member] | Adjustments [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	(203.4)	(180.3)	(73.0)
Increase/(decrease) in operating expenses	(203.4)	(180.3)	(73.0)
Revision Adjustment [Member] | Consolidated [Member]
Condensed Financial Statements, Captions [Line Items]
Increase/(decrease) in operating revenues	0	0	0
Increase/(decrease) in operating expenses	$ 0	$ 0	$ 0