Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2013

Property, Plant and Equipment [Abstract]

Schedule of Property, Plant and Equipment

Property, plant and equipment includes the following:

	Weighted Average Useful	December 31,
	Lives (Years)	2013		2012
		(in millions)
Transmission	41	$	1,926	$	1,851
Distribution	29	5,848		5,548
Other	14	967		805
Total		8,741		8,204
Accumulated depreciation		2,907		2,839
Property, plant and equipment, net		$	5,834	$	5,365

Depreciation and Amortization

The following table presents depreciation and amortization expense for 2013, 2012 and 2011:

	Year Ended December 31,
	2013		2012		2011
	(in millions)
Depreciation expense	$	280	$	265	$	257
Amortization of securitized regulatory assets	383		442		308
Other amortization	22		22		22
Total depreciation and amortization	$	685	$	729	$	587

Asset Retirement Obligation

A reconciliation of the changes in the asset retirement obligation (ARO) liability is as follows (in millions):

	December 31,
	2013		2012
Beginning balance	$	29	$	23
Accretion expense	1		1
Revisions in estimates of cash flows	3		5
Ending balance	$	33	$	29