CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Operating revenues
Revenues	$ 3,088	$ 3,018	$ 2,973
Costs and expenses
Operating and maintenance	2,140	1,799	1,389
Depreciation and amortization	855	818	832
General and administrative	193	188	156
Total costs and expenses	3,188	2,805	2,377
Loss on impairment	(609)	(1,464)	(1,498)
Loss on disposal of assets, net	(12)		(1,603)
Operating loss	(721)	(1,251)	(2,505)
Other income (expense), net
Interest income	43	53	43
Interest expense, net of amounts capitalized	(660)	(620)	(491)
Loss on retirement of debt	(41)	(3)	(55)
Other, net	181	46	5
Total other income (expense), net	(477)	(524)	(498)
Loss before income tax expense	(1,198)	(1,775)	(3,003)
Income tax expense	59	228	94
Net loss	(1,257)	(2,003)	(3,097)
Net income (loss) attributable to noncontrolling interest	(2)	(7)	30
Net loss attributable to controlling interest	$ (1,255)	$ (1,996)	$ (3,127)
Loss per share
Basic (in dollars per share)	$ (2.05)	$ (4.27)	$ (8.00)
Diluted (in dollars per share)	$ (2.05)	$ (4.27)	$ (8.00)
Weighted-average shares outstanding
Basic (in shares)	612	468	391
Diluted (in shares)	612	468	391
Contract drilling revenues
Operating revenues
Revenues	$ 3,088	$ 3,018	$ 2,731
Other revenues
Operating revenues
Revenues			$ 242