Comprehensive Income (Details) (USD $) In Millions	3 Months Ended	6 Months Ended
Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010
After-tax components of comprehensive income
Net income	$ 292.2	$ 214.2	$ 470.9	$ 350.9
Net increase (decrease) in fair value of cash flow hedges, net of income taxes	64.3	(187.2)	96.8	(132.2)
Net unrealized (losses) gains on available-for-sale securities, net of income taxes	(0.8)		0.2
Amortization of actuarial loss and prior service cost associated with postretirement plans and workers' compensation obligations, net of income taxes	10.0	8.5	23.5	16.0
Comprehensive income	$ 365.7	$ 35.5	$ 591.4	$ 234.7

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

+ References+ Details

The increase (decrease) in accumulated comprehensive income during the period related to pension and other postretirement benefit plans, after tax. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

+ References+ Details

- Definition

Net of tax effect change in accumulated gains and losses from derivative instruments designated and qualifying as the effective portion of cash flow hedges after taxes. A cash flow hedge is a hedge of the exposure to variability in the cash flows of a recognized asset or liability or a forecasted transaction that is attributable to a particular risk. The change includes an entity's share of an equity investee's increase or decrease in deferred hedging gains or losses. While for technical reasons this element has no balance attribute, the default assumption is a credit balance consistent with its label.

+ References

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+ Details

- Definition

Change in accumulated gains and losses from derivative instrument designated and qualifying as the effective portion of cash flow hedges, net of tax effect. The after tax effect change includes an entity's share of an equity investee's Increase or Decrease in deferred hedging gains or losses.

+ References

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+ Details

- Definition

The consolidated profit or loss for the period, net of income taxes, including the portion attributable to the noncontrolling interest.

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+ Details