Schedule I - Condensed Financial Information Of Parent (Balance Sheet) (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
ASSETS
Cash and cash equivalents	$ 9	$ 292	$ 5	$ 30
Miscellaneous accounts and notes receivable	63	98
Other current assets	98	88
Total current assets	1,593	1,917
Accumulated deferred income taxes, net	7	6
Other assets	538	575
TOTAL ASSETS	24,699	23,640
LIABILITIES AND EQUITY
Short-term debt	558	301
Other current liabilities	248	279
Total current liabilities	2,674	2,093
Long-term Debt, Net	6,595	6,880
Pension and other postretirement benefits	769	580
Other deferred credits and liabilities	477	531
Commitments and Contingencies
Retained earnings	1,568	1,331
Accumulated other comprehensive loss	(23)	(3)
Total equity	7,245	7,088	6,855
TOTAL LIABILITIES AND EQUITY	24,699	23,640
Parent Company
ASSETS
Cash and cash equivalents	1	0	$ 1	$ 11
Advances to money pool	27	0
Accounts receivable - affiliates	31	53
Miscellaneous accounts and notes receivable	26	3
Other current assets	8	9
Total current assets	93	65
Investments in subsidiaries	7,498	7,227
Note receivable - affiliates	350	290
Accumulated deferred income taxes, net	419	426
Other assets	135	158
TOTAL ASSETS	8,495	8,166
LIABILITIES AND EQUITY
Short-term debt	507	301
Borrowings from money pool	33	14
Accounts payable – affiliates	13	75
Other current liabilities	17	22
Total current liabilities	570	412
Long-term Debt, Net	694	694
Pension and other postretirement benefits	45	33
Other deferred credits and liabilities	83	81
Total liabilities	1,392	1,220
Common stock, $.01 par value, 400.0 shares authorized – shares outstanding of 242.6	2	2
Other paid-in capital, principally premium on common stock	5,556	5,616
Retained earnings	1,568	1,331
Accumulated other comprehensive loss	(23)	(3)
Total equity	7,103	6,946
TOTAL LIABILITIES AND EQUITY	$ 8,495	$ 8,166