v3.25.4
Cover
Feb. 09, 2026
Cover [Abstract]  
Document Type 8-K
Amendment Flag false
Document Period End Date Feb. 09, 2026
Entity File Number 001-38373
Entity Registrant Name TRANSOCEAN LTD.
Entity Central Index Key 0001451505
Entity Tax Identification Number 98-0599916
Entity Incorporation, State or Country Code V8
Entity Address, Address Line One Turmstrasse 30
Entity Address, City or Town Steinhausen
Entity Address, Country CH
Entity Address, Postal Zip Code CH-6312
City Area Code +41 (41)
Local Phone Number 749-0500
Written Communications false
Soliciting Material true
Pre-commencement Tender Offer false
Pre-commencement Issuer Tender Offer false
Title of 12(b) Security Shares, $0.10 par value
Trading Symbol RIG
Security Exchange Name NYSE
Entity Emerging Growth Company false