Property, Plant And Equipment (Tables)

12 Months Ended

Dec. 31, 2011

Property, Plant And Equipment [Abstract]

Schedule Of Property, Plant And Equipment

	Original Cost		Accumulated Depreciation		Net Book Value
	(millions of dollars)
At December 31, 2011
Generation	$	108	$	82	$	26
Distribution		7,832		2,848		4,984
Transmission		2,462		834		1,628
Gas		429		133		296
Construction work in progress		742		—		742
Non-operating and other property		1,282		738		544
Total	$	12,855	$	4,635	$	8,220
At December 31, 2010
Generation	$	105	$	72	$	33
Distribution		7,567		2,749		4,818
Transmission		2,307		793		1,514
Gas		413		125		288
Construction work in progress		553		—		553
Non-operating and other property		1,175		708		467
Total	$	12,120	$	4,447	$	7,673