Commitments and Contingent Liabilities (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2014
Status of company's rigs under construction [Abstract]
Total estimated project costs		$ 2,220
Total costs incurred through September 30, 2014		1,191
Projected costs for the remainder of 2014		537
Projected costs in 2015		492
Total future costs		1,029
Capital expenditures for the remainder of 2014	77	77
Outstanding letters of credit	25.6	25.6
Tax benefits recognized from settlement	46
Rowan Resolute [Member]
Status of company's rigs under construction [Abstract]
Total estimated project costs		723
Total costs incurred through September 30, 2014		682
Projected costs for the remainder of 2014		41
Projected costs in 2015		0
Total future costs		41
Rowan Reliance [Member]
Status of company's rigs under construction [Abstract]
Total estimated project costs		742
Total costs incurred through September 30, 2014		277
Projected costs for the remainder of 2014		458
Projected costs in 2015		7
Total future costs		465
Rowan Relentless [Member]
Status of company's rigs under construction [Abstract]
Total estimated project costs		755
Total costs incurred through September 30, 2014		232
Projected costs for the remainder of 2014		38
Projected costs in 2015		485
Total future costs		523
Current Income Tax Receivable [Member]
Status of company's rigs under construction [Abstract]
Tax benefits recognized from settlement	35
Long-Term Receivables [Member]
Status of company's rigs under construction [Abstract]
Tax benefits recognized from settlement	(47)
Other Long-term Liabilities [Member]
Status of company's rigs under construction [Abstract]
Tax benefits recognized from settlement	$ 58