Condensed Consolidated Statement of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Cash flows from operating activities:
Net income (loss)	$ 456	$ 294
Adjustments to reconcile net income (loss) to net cash provided by (used for) operating activities:
Depreciation, amortization and accretion	787	753
(Gains) losses on retirement of long-term obligations	2	74
Amortization of Debt Issuance Costs and Discounts	1	4
Stock-based compensation expense	62	47
Asset write-down charges	12	9
Deferred income tax (benefit) provision	1	1
Other non-cash adjustments	3	1
Changes in assets and liabilities, excluding the effects of acquisitions:
Increase (decrease) in accrued interest	18	22
Increase (decrease) in accounts payable	6	3
Increase (decrease) in other liabilities	30	53
Decrease (increase) in receivables	(89)	(59)
Decrease (increase) in other assets	(62)	(91)
Net cash provided by (used for) operating activities	1,227	1,111
Cash flows from investing activities:
Payments for acquisitions, net of cash acquired	(13)	(18)
Capital expenditures	(998)	(763)
Other investing activities, net	1	3
Net cash provided by (used for) investing activities	(1,010)	(778)
Cash flows from financing activities:
Proceeds from issuance of long-term debt	995	1,743
Principal payments on debt and other long-term obligations	(36)	(47)
Purchases and redemptions of long-term debt	(12)	(1,318)
Borrowings under revolving credit facility	1,195	485
Payments under revolving credit facility	(1,785)	(1,150)
Proceeds from Issuance of Commercial Paper	500	0
Payments for financing costs	(14)	(20)
Net proceeds from issuance of common stock	0	841
Purchases of Common Stock	(43)	(34)
Dividends/distributions paid on common stock	(944)	(879)
Dividends paid on preferred stock	(57)	(57)
Net cash provided by (used for) financing activities	(201)	(436)
Net increase (decrease) in cash, cash equivalents, and restricted cash	16	(103)
Cash and Cash Equivalents at Beginning of Period	413	440
Cash and Cash Equivalents at End of Period	429	336
Effect of Exchange Rate on Cash and Cash Equivalents [Abstract]
Effect of exchange rate changes	$ 0	$ (1)