Consolidated Statements of Cash Flows - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015
Cash Flows from Operating Activities:
Net Income	$ 273	$ 109
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	611	576
Non-cash compensation expense attributable to stock awards	78	58
Loss on modification and extinguishment of debt	40	163
Accretion of debt discount and amortization of debt issuance costs	10	13
Accrued interest on long-term debt, net	23	(40)
Deferred income taxes	111	(10)
(Gain) Loss on sale of property, plant and equipment and other assets	(1)	1
Other, net	(3)	30
Changes in working capital items:
Receivables	(69)	(32)
Other current assets	(40)	(36)
Accounts payable	132	(22)
Deferred revenue	42	(4)
Other current liabilities	(66)	(82)
Net Cash Provided by Operating Activities	1,141	724
Cash Flows from Investing Activities:
Capital expenditures	(664)	(571)
Change in restricted cash and securities, net	11	(24)
Proceeds from sale of property, plant and equipment and other assets	1	2
Net Cash Used in Investing Activities	(652)	(593)
Cash Flows from Financing Activities:
Long-term debt borrowings, net of issuance costs	764	3,948
Payments on and repurchases of long-term debt and capital leases	(816)	(4,098)
Net Cash Used in Financing Activities	(52)	(150)
Effect of Exchange Rates on Cash and Cash Equivalents	0	(12)
Net Change in Cash and Cash Equivalents	437	(31)
Cash and Cash Equivalents at Beginning of Period	854	580
Cash and Cash Equivalents at End of Period	1,291	549
Supplemental Disclosure of Cash Flow Information:
Cash interest paid	245	366
Income taxes paid, net of refunds	18	29
Non-cash Financing Activities:
Capital lease obligations incurred	0	6
Long-term debt conversion into equity	0	333
Accrued interest conversion into equity	$ 0	$ 10