Segment Information (Schedule Of Segment Reporting Information) (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenues	$ 458.5	$ 457.5	$ 875.5	$ 928.6
Operating Expenses [Abstract]
Contract drilling (exclusive of depreciation)	344.3	291.3	669.5	569.4
Depreciation	120.7	107.9	235.9	217.1
General and administrative	26.1	30.5	54.0	56.5
OPERATING INCOME (LOSS)	(32.6)	27.8	(83.9)	85.6
Property and equipment, net	12,783.9	11,059.0	12,783.9	11,059.0	$ 12,873.7
Floaters
Segment Reporting Information [Line Items]
Revenues	284.9	264.0	543.9	548.8
Operating Expenses [Abstract]
Contract drilling (exclusive of depreciation)	203.7	145.6	388.8	292.0
Depreciation	80.8	72.0	156.1	144.8
General and administrative	0.0	0.0	0.0	0.0
OPERATING INCOME (LOSS)	0.4	46.4	(1.0)	112.0
Property and equipment, net	9,574.9	8,493.2	9,574.9	8,493.2
Jackups
Segment Reporting Information [Line Items]
Revenues	158.7	178.9	302.1	350.7
Operating Expenses [Abstract]
Contract drilling (exclusive of depreciation)	126.8	132.3	253.7	250.9
Depreciation	36.5	31.6	73.0	63.7
General and administrative	0.0	0.0	0.0	0.0
OPERATING INCOME (LOSS)	(4.6)	15.0	(24.6)	36.1
Property and equipment, net	3,167.0	2,515.3	3,167.0	2,515.3
Other
Segment Reporting Information [Line Items]
Revenues	14.9	14.6	29.5	29.1
Operating Expenses [Abstract]
Contract drilling (exclusive of depreciation)	13.8	13.4	27.0	26.5
Depreciation	0.0	0.0	0.0	0.0
General and administrative	0.0	0.0	0.0	0.0
OPERATING INCOME (LOSS)	1.1	1.2	2.5	2.6
Property and equipment, net	0.0	0.0	0.0	0.0
Operating Segments Total
Segment Reporting Information [Line Items]
Revenues	458.5	457.5	875.5	928.6
Operating Expenses [Abstract]
Contract drilling (exclusive of depreciation)	344.3	291.3	669.5	569.4
Depreciation	117.3	103.6	229.1	208.5
General and administrative	0.0	0.0	0.0	0.0
OPERATING INCOME (LOSS)	(3.1)	62.6	(23.1)	150.7
Property and equipment, net	12,741.9	11,008.5	12,741.9	11,008.5
Reconciling Items
Segment Reporting Information [Line Items]
Revenues	0.0	0.0	0.0	0.0
Operating Expenses [Abstract]
Contract drilling (exclusive of depreciation)	0.0	0.0	0.0	0.0
Depreciation	3.4	4.3	6.8	8.6
General and administrative	26.1	30.5	54.0	56.5
OPERATING INCOME (LOSS)	(29.5)	(34.8)	(60.8)	(65.1)
Property and equipment, net	$ 42.0	$ 50.5	$ 42.0	$ 50.5

The expense recognized in the current period that allocates the cost of a tangible asset used in providing revenue generating services over the asset's useful life.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3602-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.2(d))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_CostOfServicesDepreciation
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Costs of generating revenue from oil and gas-related services including well services (such as drilling, rigs and analytic evaluations), transportation, and other supporting contractor services, during the reporting period.

+ References

No definition available.

+ Details

Name:	us-gaap_CostOfServicesOilAndGas
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The aggregate total of expenses of managing and administering the affairs of an entity, including affiliates of the reporting entity, which are not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.4)
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_GeneralAndAdministrativeExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_OperatingExpensesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The net result for the period of deducting operating expenses from operating revenues.

+ References

No definition available.

+ Details

Name:	us-gaap_OperatingIncomeLoss
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(13))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(14))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(8))
-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

Reference 4: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 360
-SubTopic 10
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

+ Details

Name:	us-gaap_PropertyPlantAndEquipmentNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Revenue from oil and gas-related services including well services (such as drilling, rigs and analytic evaluations), transportation, and other supporting contractor services, during the reporting period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 225
-SubTopic 10
-Section S99
-Paragraph 2
-Subparagraph (SX 210.5-03.1(d))
-URI http://asc.fasb.org/extlink&oid=63488584&loc=d3e20235-122688

+ Details

Name:	us-gaap_RevenueOilAndGasServices
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

Name:	us-gaap_SegmentReportingInformationLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=esv_FloatersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=esv_JackupsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=us-gaap_AllOtherSegmentsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=esv_OperatingSegmentsTotalMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementBusinessSegmentsAxis=esv_ReconcilingItemsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: