Supplemental Guarantor/Non-Guarantor Financial Information Supplemental Guarantor/Non-Guarantor Financial Information (Details 3) (Details) (USD $) In Millions, 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
Condensed Financial Statements, Captions [Line Items]
Net (loss) income	$ (1,002.8)	$ 41.6	$ 207.8	$ 178.3	$ 194.0	$ 281.4	$ 292.2	$ 178.7	$ (575.1)	$ 946.3	$ 802.2
Unrealized holding losses on available-for-sale securities									(15.5)	(5.8)	0
Less: Reclassification for realized losses (gains) included in net income									22.5	(0.9)	0
Net change in unrealized gains (losses) on available-for-sale securities									7.0	(6.7)	0
Increase in fair value of cash flow hedges, net of tax									350.4	291.9	229.9
Less: Reclassification for realized gains included in net income									(298.6)	(251.0)	(102.4)
Net unrealized (losses) gains on cash flow hedges									51.8	40.9	127.5
Prior service cost (credit) for the period									20.1	0.9	(4.9)
Net actuarial (loss) gain for the period									0	(150.1)	(41.3)
Amortization of actuarial loss and prior service cost									55.4	40.5	34.3
Postretirement plan and worker's compensation obligations									75.5	(108.7)	(11.9)
Foreign currency translation adjustment									19.1	0	0
Other comprehensive income from investment in subsidiaries									0	0	0
Other comprehensive (loss) income, net of taxes									153.4	(74.5)	115.6
Comprehensive (loss) income									(421.7)	871.8	917.8
Less: Comprehensive (loss) income attributable to noncontrolling interests									10.6	(11.4)	28.2
Comprehensive (loss) income attributable to common stockholders									(432.3)	883.2	889.6
Parent Company [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									(585.7)	957.7	774.0
Unrealized holding losses on available-for-sale securities									(15.5)	(6.0)
Less: Reclassification for realized losses (gains) included in net income									22.5	(0.9)
Net change in unrealized gains (losses) on available-for-sale securities									7.0	(6.9)
Increase in fair value of cash flow hedges, net of tax									205.9	142.0	408.2
Less: Reclassification for realized gains included in net income									(249.1)	(241.9)	(85.8)
Net unrealized (losses) gains on cash flow hedges									(43.2)	(99.9)	322.4
Prior service cost (credit) for the period									0	0	0
Net actuarial (loss) gain for the period									0	0	0
Amortization of actuarial loss and prior service cost									0	0	0
Postretirement plan and worker's compensation obligations									0	0	0
Foreign currency translation adjustment									0
Other comprehensive income from investment in subsidiaries									189.6	32.3	(206.8)
Other comprehensive (loss) income, net of taxes									153.4	(74.5)	115.6
Comprehensive (loss) income									(432.3)	883.2	889.6
Less: Comprehensive (loss) income attributable to noncontrolling interests									0	0	0
Comprehensive (loss) income attributable to common stockholders									(432.3)	883.2	889.6
Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									566.9	454.6	393.1
Unrealized holding losses on available-for-sale securities									0	0
Less: Reclassification for realized losses (gains) included in net income									0	0
Net change in unrealized gains (losses) on available-for-sale securities									0	0
Increase in fair value of cash flow hedges, net of tax									0	0	13.2
Less: Reclassification for realized gains included in net income									0	0	(7.0)
Net unrealized (losses) gains on cash flow hedges									0	0	6.2
Prior service cost (credit) for the period									20.1	0.9	(4.9)
Net actuarial (loss) gain for the period									(0.9)	(148.6)	(40.9)
Amortization of actuarial loss and prior service cost									54.5	39.4	33.3
Postretirement plan and worker's compensation obligations									73.7	(108.3)	(12.5)
Foreign currency translation adjustment									0
Other comprehensive income from investment in subsidiaries									0	0	0
Other comprehensive (loss) income, net of taxes									73.7	(108.3)	(6.3)
Comprehensive (loss) income									640.6	346.3	386.8
Less: Comprehensive (loss) income attributable to noncontrolling interests									0	0	0
Comprehensive (loss) income attributable to common stockholders									640.6	346.3	386.8
Non-Guarantor Subsidiaries [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									(1,276.3)	415.5	462.1
Unrealized holding losses on available-for-sale securities									0	0.2
Less: Reclassification for realized losses (gains) included in net income									0	0
Net change in unrealized gains (losses) on available-for-sale securities									0	0.2
Increase in fair value of cash flow hedges, net of tax									144.5	149.9	(191.5)
Less: Reclassification for realized gains included in net income									(49.5)	(9.1)	(9.6)
Net unrealized (losses) gains on cash flow hedges									95.0	140.8	(201.1)
Prior service cost (credit) for the period									0	0	0
Net actuarial (loss) gain for the period									0.9	(1.5)	(0.4)
Amortization of actuarial loss and prior service cost									0.9	1.1	1.0
Postretirement plan and worker's compensation obligations									1.8	(0.4)	0.6
Foreign currency translation adjustment									19.1
Other comprehensive income from investment in subsidiaries									0	0	0
Other comprehensive (loss) income, net of taxes									115.9	140.6	(200.5)
Comprehensive (loss) income									(1,160.4)	556.1	261.6
Less: Comprehensive (loss) income attributable to noncontrolling interests									10.6	(11.4)	28.2
Comprehensive (loss) income attributable to common stockholders									(1,171.0)	567.5	233.4
Consolidation, Eliminations [Member]
Condensed Financial Statements, Captions [Line Items]
Net (loss) income									720.0	(881.5)	(827.0)
Unrealized holding losses on available-for-sale securities									0	0
Less: Reclassification for realized losses (gains) included in net income									0	0
Net change in unrealized gains (losses) on available-for-sale securities									0	0
Increase in fair value of cash flow hedges, net of tax									0	0	0
Less: Reclassification for realized gains included in net income									0	0	0
Net unrealized (losses) gains on cash flow hedges									0	0	0
Prior service cost (credit) for the period									0	0	0
Net actuarial (loss) gain for the period									0	0	0
Amortization of actuarial loss and prior service cost									0	0	0
Postretirement plan and worker's compensation obligations									0	0	0
Foreign currency translation adjustment									0
Other comprehensive income from investment in subsidiaries									(189.6)	(32.3)	206.8
Other comprehensive (loss) income, net of taxes									(189.6)	(32.3)	206.8
Comprehensive (loss) income									530.4	(913.8)	(620.2)
Less: Comprehensive (loss) income attributable to noncontrolling interests									0	0	0
Comprehensive (loss) income attributable to common stockholders									$ 530.4	$ (913.8)	$ (620.2)