v3.21.1

Revenues (Disaggregation) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020	Dec. 31, 2020
Revenue
Recognized pre-operating costs	$ 14	$ 9
Unrecognized pre-operating costs	14		$ 20
Contract drilling revenues	653	759
Ultra-deepwater floaters
Revenue
Contract drilling revenues	436	528
Harsh environment floaters
Revenue
Contract drilling revenues	217	220
Midwater floaters
Revenue
Contract drilling revenues		11
U.S.
Revenue
Contract drilling revenues	270	287
U.S. | Ultra-deepwater floaters
Revenue
Contract drilling revenues	266	287
U.S. | Harsh environment floaters
Revenue
Contract drilling revenues	4
Norway
Revenue
Contract drilling revenues	202	207
Norway | Harsh environment floaters
Revenue
Contract drilling revenues	202	207
Other
Revenue
Contract drilling revenues	181	265
Other | Ultra-deepwater floaters
Revenue
Contract drilling revenues	170	241
Other | Harsh environment floaters
Revenue
Contract drilling revenues	$ 11	13
Other | Midwater floaters
Revenue
Contract drilling revenues		$ 11

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