CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015
OPERATING ACTIVITIES
Net income	$ 236	$ 192
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	976	1,040
Impairment of assets	0	8
Deferred income taxes	11	37
Provision for uncollectible accounts	46	42
Net long-term debt issuance costs and premium amortization	(1)	(2)
Share-based compensation	18	18
Changes in current assets and liabilities:
Accounts receivable	26	(27)
Accounts payable	78	(80)
Accrued income and other taxes	160	136
Other current assets and liabilities, net	(72)	(16)
Retirement benefits	(21)	(9)
Changes in other noncurrent assets and liabilities, net	(35)	(10)
Other, net	1	7
Net cash provided by operating activities	1,423	1,336
INVESTING ACTIVITIES
Payments for property, plant and equipment and capitalized software	(611)	(616)
Proceeds from sale of property	7	14
Other, net	(1)	(8)
Net cash used in investing activities	(605)	(610)
FINANCING ACTIVITIES
Net proceeds from issuance of long-term debt	227	594
Payments of long-term debt	(25)	(386)
Net payments on credit facility and revolving line of credit	(410)	(425)
Dividends paid	(290)	(304)
Net proceeds from issuance of common stock	4	8
Repurchase of common stock	(12)	(185)
Other, net	0	(1)
Net cash used in financing activities	(506)	(699)
Net increase in cash and cash equivalents	312	27
Cash and cash equivalents at beginning of period	126	128
Cash and cash equivalents at end of period	438	155
Supplemental cash flow information:
Income taxes paid, net	(11)	(5)
Interest paid (net of capitalized interest of $12 and $13)	$ (262)	$ (270)