CONSOLIDATED CONDENSED STATEMENTS OF CASH FLOWS - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018
Statement of Cash Flows [Abstract]
Cash flows provided by operating activities	$ 613	$ 404
Cash flows from investing activities
Acquisitions of property and equipment, net of change in related payables	(434)	(215)
Proceeds from the sale and maturity of investments	7	28
Payments to acquire investments	(9)	(16)
Payments for (Proceeds from) Other Investing Activities	4	0
Cash flows used in investing activities	(432)	(203)
Cash flows from financing activities
Proceeds from long-term debt and revolving credit facilities	0	467
Debt issuance costs and fees	0	5
Repayments of long-term debt and revolving credit facilities	(133)	(500)
Proceeds from the issuance of common stock	27	4
Repurchase of common stock	0	31
Taxes paid related to net share settlement of equity awards	(15)	(12)
Financing obligation payments	(10)	(5)
Contributions from noncontrolling interest owners	0	20
Distributions to noncontrolling interest owners	(2)	0
Cash flows used in financing activities	(133)	(62)
Change in cash, cash equivalents, and restricted cash classified as held for sale	(4)	0
Net increase in cash, cash equivalents, and restricted cash	44	139
Cash, cash equivalents, and restricted cash, beginning of period	1,657	2,709
Cash, cash equivalents, and restricted cash, end of period	1,701	2,848
Supplemental Cash Flow Information:
Cash paid for interest	579	581
Cash paid for income taxes	2	4
Change in accrued capital expenditures	$ 10	$ 10