XML 148 R137.htm IDEA: XBRL DOCUMENT v3.19.1

21. Employees benefits (Details 11)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
SummaryOfEmployeeBenefitsLineItems [Line Items]
Discount rate	4.91%	5.35%	5.74%
Inflation rate	4.01%	3.96%	4.87%
Future salary increase	6.09%	6.04%	6.97%
Mortality table	AT-2000	AT-2000	AT-2000
Unfunded plan
SummaryOfEmployeeBenefitsLineItems [Line Items]
Discount rate	4.84%	5.30%	5.71%
Inflation rate	4.01%	3.96%	4.87%
Future salary increase	6.09%	6.04%	6.97%
Mortality table	AT-2000	AT-2000	AT-2000

X

- References

No definition available.

+ Details

Name:	SBS_ActuarialAssumptionOfMortalityRates2
Namespace Prefix:	SBS_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- References

No definition available.

+ Details

Name:	SBS_SummaryOfEmployeeBenefitsLineItems
Namespace Prefix:	SBS_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

X

- Definition

The discount rate used as the significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit obligation, at present value; Actuarial assumptions [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2018-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_144&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_ActuarialAssumptionOfDiscountRates
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The expected rate of inflation that is used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2018-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_144&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_ActuarialAssumptionOfExpectedRatesOfInflation
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Definition

The expected rate of salary increases used as a significant actuarial assumption to determine the present value of a defined benefit obligation. [Refer: Defined benefit plans [member]; Defined benefit obligation, at present value; Actuarial assumptions [member]]

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Name IAS
-Number 19
-IssueDate 2018-01-01
-Paragraph 144
-URI http://eifrs.ifrs.org/eifrs/XBRL?type=IAS&num=19&date=2018-03-01&anchor=para_144&doctype=Standard
-URIDate 2018-03-16

+ Details

Name:	ifrs-full_ActuarialAssumptionOfExpectedRatesOfSalaryIncreases
Namespace Prefix:	ifrs-full_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

X

- Details

Name:	ifrs-full_DefinedBenefitPlansAxis=SBS_UnfundedPlansMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: