Regulatory Assets and Liabilities (Tables)

12 Months Ended

Dec. 31, 2011

Regulatory Assets and Liabilities Disclosure [Abstract]

Regulatory Assets Included on the Consolidated Balance Sheets

Regulatory assets included on the consolidated balance sheets are:

	December 31,
(in millions)	2011		2010
Current:
Regulatory balancing accounts	$	223	$	213
Energy derivatives	264		162
Other	7		3
Total Current	494		378
Long-term:
Deferred income taxes – net	2,020		1,855
Pensions and other postretirement benefits	1,703		1,097
Unamortized investments – net	484		460
Unamortized loss on reacquired debt	249		268
Energy derivatives	487		177
Nuclear-related investment – net	156		154
Regulatory balancing accounts	69		56
Other	298		280
Total Long-term	5,466		4,347
Total Regulatory Assets	$	5,960	$	4,725

Regulatory Liabilities Included on the Consolidated Balance Sheets

Regulatory liabilities included on the consolidated balance sheets are:

	December 31,
(in millions)	2011		2010
Current:
Regulatory balancing accounts	$	661	$	733
Other	9		5
Total Current	670		738
Long-term:
Costs of removal	2,697		2,623
Asset Retirement Obligations	1,105		1,099
Regulatory balancing accounts	864		802
Other	4		—
Total Long-term	4,670		4,524
Total Regulatory Liabilities	$	5,340	$	5,262