Pension Plans and Postretirement Benefits Other Than Pensions (Tables)

3 Months Ended

Mar. 31, 2012

Defined Benefit Pension Plans and Defined Benefit Postretirement Plans Disclosure [Abstract]

Expense Components for Pension Plans

Expense components are:

	Three months ended March 31,
(in millions)	2012			2011
Service cost	$	43		$	43
Interest cost	49			52
Expected return on plan assets	(59		)	(60		)
Amortization of prior service cost	1			2
Amortization of net loss	18			6
Expense under accounting standards	52			43
Regulatory adjustment (deferred)	25			(6		)
Total expense recognized	$	77		$	37

Expense Components for Postretirement Benefits Other than Pensions

Expense components are:

	Three months ended March 31,
(in millions)	2012			2011
Service cost	$	13		$	11
Interest cost	30			33
Expected return on plan assets	(27		)	(28		)
Amortization of prior service credit	(9		)	(9		)
Amortization of net loss	12			9
Total expense	$	19		$	16