Accumulated Other Comprehensive Income (Loss)

3 Months Ended

Mar. 31, 2013

Disclosure Text Block [Abstract]

Accumulated Other Comprehensive Income (Loss)

10.  Accumulated Other Comprehensive Income (Loss)

The following summarizes the after-tax changes in the balances of each component of accumulated other comprehensive income (loss):

			Interest-rate
			Derivatives		Pension and
			Previously		Other
			Subject to Hedge		Postretirement
millions			Accounting		Plans		Total
Balance at December 31, 2012			$	(61)	$	(579)	$	(640)
	Reclassifications from accumulated other
		comprehensive income (loss)		2		19		21
Balance at March 31, 2013			$	(59)	$	(560)	$	(619)