Condensed Consolidated Statements of Financial Position (Unaudited) - USD ($) $ in Millions	Sep. 30, 2015	Dec. 31, 2014	Sep. 30, 2014
Current assets
Cash and cash equivalents	$ 19	$ 31	$ 32
Receivables
Energy marketing	475	779	544
Natural gas, unbilled revenues and other	339	797	409
Less allowance for uncollectible accounts	34	35	37
Total receivables, net	780	1,541	916
Inventories
Natural gas	632	694	777
Other	27	22	19
Total inventories	659	716	796
Derivative instruments	151	245	102
Prepaid expenses	74	223	78
Regulatory assets	64	83	105
Other	29	47	60
Total current assets	1,776	2,886	2,089
Long-term assets and other deferred debits
Property, plant and equipment	12,141	11,552	11,352
Less accumulated depreciation	2,560	2,462	2,427
Property, plant and equipment, net	9,581	9,090	8,925
Goodwill	1,813	1,827	1,827
Regulatory assets	637	631	637
Intangible assets	113	125	130
Other	286	329	324
Total long-term assets and other deferred debits	12,430	12,002	11,843
Total assets	14,206	14,888	13,932
Current liabilities
Short-term debt	886	1,175	681
Current portion of long-term debt	425	200	200
Energy marketing trade payables	502	777	612
Other accounts payable – trade	274	312	298
Accrued expenses	177	229	173
Customer deposits and credit balances	150	125	122
Regulatory liabilities	139	112	118
Accrued environmental remediation liabilities	73	87	82
Derivative instruments	58	88	45
Other	118	114	131
Total current liabilities	2,802	3,219	2,462
Long-term liabilities and other deferred credits
Long-term debt	3,150	3,581	3,584
Accumulated deferred income taxes	1,767	1,724	1,655
Regulatory liabilities	1,608	1,601	1,567
Accrued pension and retiree welfare benefits	528	525	406
Accrued environmental remediation liabilities	346	327	372
Other	95	83	84
Total long-term liabilities and other deferred credits	7,494	7,841	7,668
Total liabilities and other deferred credits	$ 10,296	$ 11,060	$ 10,130
Commitments, guarantees and contingencies (see Note 11)
Equity
Common stock, $5 par value; 750,000,000 shares authorized; outstanding: 120,249,058 shares at September 30, 2015, 119,647,149 shares at December 31, 2014, and 119,564,666 shares at September 30, 2014	$ 602	$ 599	$ 599
Additional paid-in capital	2,095	2,087	2,080
Retained earnings	1,375	1,312	1,222
Accumulated other comprehensive loss	(195)	(206)	(133)
Treasury shares, at cost: 216,523 shares at September 30, 2015, December 31, 2014, and September 30, 2014	(8)	(8)	(8)
Total common shareholders’ equity	3,869	3,784	3,760
Noncontrolling interest	41	44	42
Total equity	3,910	3,828	3,802
Total liabilities and equity	$ 14,206	$ 14,888	$ 13,932