CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015
OPERATING ACTIVITIES
Net income	$ 584	$ 540
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	2,958	3,136
Impairment of assets	1	9
Deferred income taxes	32	93
Provision for uncollectible accounts	144	128
Net long-term debt issuance costs and premium amortization	2	(3)
Net loss on early retirement of debt	(27)	0
Share-based compensation	60	57
Changes in current assets and liabilities:
Accounts receivable	(158)	(91)
Accounts payable	52	(84)
Accrued income and other taxes	1	250
Other current assets and liabilities, net	(24)	123
Retirement benefits	(143)	(134)
Changes in other noncurrent assets and liabilities, net	(41)	(54)
Other, net	17	(14)
Net cash provided by operating activities	3,512	3,956
INVESTING ACTIVITIES
Payments for property, plant and equipment and capitalized software	(2,010)	(2,039)
Cash paid for acquisitions	(24)	(4)
Proceeds from sale of property	22	29
Other, net	0	(8)
Net cash used in investing activities	(2,012)	(2,022)
FINANCING ACTIVITIES
Net proceeds from issuance of long-term debt	2,161	990
Payments of long-term debt	(2,436)	(535)
Net payments on credit facility and revolving line of credit	(325)	(725)
Dividends paid	(876)	(905)
Proceeds from issuance of common stock	5	11
Repurchase of common stock and shares withheld to satisfy tax withholdings	(15)	(541)
Other, net	0	(2)
Net cash used in financing activities	(1,486)	(1,707)
Net increase in cash and cash equivalents	14	227
Cash and cash equivalents at beginning of period	126	128
Cash and cash equivalents at end of period	140	355
Supplemental cash flow information:
Income taxes paid, net	(344)	(54)
Interest paid (net of capitalized interest of $38 and $41)	$ (922)	$ (914)