Property, Plant and Equipment (Tables)

12 Months Ended

Dec. 31, 2019

Property, Plant and Equipment [Abstract]

Property, Pland and Equipment with Useful Life Classification

The following table summarizes the components of the electric generation and distribution assets and other property, plant and equipment (in millions) with their estimated useful lives (in years). The amounts are stated net of all prior asset impairment losses recognized.

		December 31,
	Estimated Useful Life	2019			2018
Electric generation and distribution facilities	5-40	$	22,869		$	22,875
Other buildings	5-50	1,612			1,651
Furniture, fixtures and equipment	3-27	319			310
Other	5-40	583			406
Total electric generation and distribution assets and other		25,383			25,242
Accumulated depreciation		(8,505		)	(8,227		)
Net electric generation and distribution assets and other		$	16,878		$	17,015

Interest Capitalized During Development And Construction

The following table summarizes depreciation expense (including the amortization of assets recorded under finance leases in 2019 or capital leases in prior periods, and the amortization of asset retirement obligations) and interest capitalized during development and construction on qualifying assets for the periods indicated (in millions):

Years Ended December 31,	2019		2018		2017
Depreciation expense	$	977	$	960	$	1,005
Interest capitalized during development and construction	238		199		139

Net Asset Value Of Regulated And Non-Regulated Assets And Accumulated Depreciation

The following table summarizes regulated and non-regulated generation and distribution property, plant and equipment and accumulated depreciation as of the dates indicated (in millions):

December 31,	2019			2018
Regulated generation and distribution assets and other, gross	$	9,246		$	8,959
Regulated accumulated depreciation	(3,707		)	(3,504		)
Regulated generation and distribution assets and other, net	5,539			5,455
Non-regulated generation and distribution assets and other, gross	16,137			16,283
Non-regulated accumulated depreciation	(4,798		)	(4,723		)
Non-regulated generation and distribution assets and other, net	11,339			11,560
Net electric generation and distribution assets and other	$	16,878		$	17,015