2.2.0.7 true Employee Benefits (Details) (USD $) 009090 - Disclosure - Employee Benefits (Details) true false In Millions false false 1 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u001 Standard http://www.xbrl.org/2003/instance pure xbrli 0 u002 Standard http://www.xbrl.org/2003/instance shares xbrli 0 u003 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 u003 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 u002 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD false false u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 4 USD true false false false Qualified and nonqualified pension plans [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 5 USD true false false false Qualified and nonqualified pension plans [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 6 USD true false false false Qualified and nonqualified pension plans [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 7 USD true false false false Qualified and nonqualified pension plans [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 8 USD true false false false Qualified and nonqualified pension plans [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 9 USD true false false false Qualified and nonqualified pension plans [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPensionPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 10 USD true false false false Postretirement benefits plan [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 11 USD true false false false Postretirement benefits plan [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 12 USD true false false false Postretirement benefits plan [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 13 USD true false false false Postretirement benefits plan [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 14 USD true false false false Postretirement benefits plan [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ false 15 USD true false false false Postretirement benefits plan [Member] us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis xbrldi http://xbrl.org/2006/xbrldi us-gaap_UnitedStatesPostretirementBenefitPlansOfUSEntityDefinedBenefitMember us-gaap_DefinedBenefitPlansDisclosuresDefinedBenefitPlansAxis explicitMember u000 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 $ 2 Notes To Financial Statements [Abstract] 0 str_NotesToFinancialStatementsAbstract str false na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 3 Discount rate, prior to decrease (in hundredths) 1 str_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRatePriorToDecrease str false na instant The interest rate used to adjust for the time value of money for the plan, prior to the decrease resulting from the transfer... false false false false false false false false false false false terselabel false 1 false true false false 0.065 0.065 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false us-types:percentItemType pure The interest rate used to adjust for the time value of money for the plan, prior to the decrease resulting from the transfer of benefit obligation to the equity method investee, due to Spinoff. This Spinoff triggered re-measurements resulting in increased expenses year-over-year. No authoritative reference available. false 4 Discount rate, subsequent to decrease (in hundredths) 1 str_DefinedBenefitPlanAssumptionsUsedCalculatingBenefitObligationDiscountRateSubsequentToDecrease str false na instant The interest rate used to adjust for the time value of money for the plan, subsequent to the decrease resulting from the... false false false false false false false false false false false terselabel false 1 false true false false 0.0575 0.0575 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false us-types:percentItemType pure The interest rate used to adjust for the time value of money for the plan, subsequent to the decrease resulting from the transfer of benefit obligation to the equity method investee, due to Spinoff. This Spinoff triggered re-measurements resulting in increased expenses year-over-year. No authoritative reference available. false 5 Amount contributed to qualified pension plan 1 us-gaap_PensionContributions us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 true true false false 30000000 30.0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary The amount of cash or cash equivalents contributed by the entity to fund its pension plans. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 false 6 Estimated qualified pension plan expense for current fiscal year 1 str_QualifiedDefinedBenefitPensionPlanEstimatedExpenseInCurrentFiscalYear str false debit instant The employer's best estimate of qualified pension plan expense for the current fiscal year. Since the company plans to fund... false false false false false false false false false false false terselabel false 1 false true false false 20800000 20.8 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary The employer's best estimate of qualified pension plan expense for the current fiscal year. Since the company plans to fund the qualified retirement plan in amounts approximately equal to the yearly expense, this element also represents estimated employer contributions expected to be paid for the current fiscal year. No authoritative reference available. false 7 Estimated nonqualified pension plan expense for current fiscal year 1 str_NonqualifiedDefinedBenefitPensionPlanEstimatedExpenseInCurrentFiscalYear str false debit instant The employer's best estimate of nonqualified pension plan expense for the current fiscal year. The nonqualified pension plan... false false false false false false false false false false false terselabel false 1 false true false false 3900000 3.9 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary The employer's best estimate of nonqualified pension plan expense for the current fiscal year. The nonqualified pension plan is unfunded. No authoritative reference available. false 10 Components of pension and postretirement benefits expense included in net income [Abstract] 3 us-gaap_DefinedBenefitPlanNetPeriodicBenefitCostAbstract us-gaap true na duration No definition available. false false false false false true false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:stringItemType string No definition available. false 11 Service cost 4 us-gaap_DefinedBenefitPlanServiceCost us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false 2300000 2.3 true false false 5 false true false false 2500000 2.5 true false false 6 false true false false 7200000 7.2 true false false 7 false true false false 7500000 7.5 true false false 8 false true false false 9600000 9.6 true false false 9 false true false false 9800000 9.8 true false false 10 false true false false 200000 0.2 true false false 11 false true false false 200000 0.2 true false false 12 false true false false 500000 0.5 true false false 13 false true false false 600000 0.6 true false false 14 false true false false 600000 0.6 true false false 15 false true false false 700000 0.7 true false false xbrli:monetaryItemType monetary The actuarial present value of benefits attributed by the pension benefit formula to services rendered by employees during the period. The portion of the expected postretirement benefit obligation attributed to employee service during the period. The service cost component is a portion of the benefit obligation and is unaffected by the funded status of the plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph a, h false 12 Interest cost 4 us-gaap_DefinedBenefitPlanInterestCost us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false 6500000 6.5 true false false 5 false true false false 7700000 7.7 true false false 6 false true false false 22300000 22.3 true false false 7 false true false false 22000000 22.0 true false false 8 false true false false 29900000 29.9 true false false 9 false true false false 29900000 29.9 true false false 10 false true false false 1000000 1.0 true false false 11 false true false false 1100000 1.1 true false false 12 false true false false 3400000 3.4 true false false 13 false true false false 3500000 3.5 true false false 14 false true false false 4500000 4.5 true false false 15 false true false false 4600000 4.6 true false false xbrli:monetaryItemType monetary The increase in a defined benefit pension plan's projected benefit obligation or a defined benefit postretirement plan's accumulated postretirement benefit obligation due to the passage of time. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph a, h false 13 Expected return on plan assets 4 us-gaap_DefinedBenefitPlanExpectedReturnOnPlanAssets us-gaap true credit duration No definition available. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false -5600000 -5.6 true false false 5 false true false false -6300000 -6.3 true false false 6 false true false false -18400000 -18.4 true false false 7 false true false false -19000000 -19.0 true false false 8 false true false false -24700000 -24.7 true false false 9 false true false false -25500000 -25.5 true false false 10 false true false false -700000 -0.7 true false false 11 false true false false -600000 -0.6 true false false 12 false true false false -1800000 -1.8 true false false 13 false true false false -1700000 -1.7 true false false 14 false true false false -2300000 -2.3 true false false 15 false true false false -2600000 -2.6 true false false xbrli:monetaryItemType monetary An amount calculated as a basis for determining the extent of delayed recognition of the effects of changes in the fair value of assets. The expected return on plan assets is determined based on the expected long-term rate of return on plan assets and the market-related value of plan assets. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h false 14 Prior service and other costs 4 us-gaap_DefinedBenefitPlanAmortizationOfPriorServiceCostCredit us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false 300000 0.3 true false false 5 false true false false 300000 0.3 true false false 6 false true false false 900000 0.9 true false false 7 false true false false 900000 0.9 true false false 8 false true false false 1200000 1.2 true false false 9 false true false false 1200000 1.2 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary The amount of the prior service cost or credit recognized in net periodic benefit cost relating to benefit changes attributable to plan participants' prior service pursuant to a plan amendment or a plan initiation. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h false 15 Recognized net-actuarial loss 4 us-gaap_DefinedBenefitPlanActuarialNetGainsLosses us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false 2800000 2.8 true false false 5 false true false false 2100000 2.1 true false false 6 false true false false 6300000 6.3 true false false 7 false true false false 5000000 5.0 true false false 8 false true false false 7900000 7.9 true false false 9 false true false false 6900000 6.9 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary The net increase or decrease of changes in the value of either the benefit obligation or the plan assets resulting from experience different from that assumed or from a change in an actuarial assumption, or the consequence of a decision to temporarily deviate from the substantive plan. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph a false 16 Settlement costs 4 us-gaap_DefinedBenefitPlanRecognizedNetGainLossDueToSettlements us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false 1100000 1.1 true false false 5 false true false false 700000 0.7 true false false 6 false true false false 1400000 1.4 true false false 7 false true false false 1300000 1.3 true false false 8 false true false false 2100000 2.1 true false false 9 false true false false 1600000 1.6 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary The amount of net (gain) loss recognized in net periodic benefit cost as a result of an irrevocable action that relieves the employer (or the plan) of primary responsibility for a benefit obligation and eliminates significant risks related to the obligation and the assets used to effect the settlement. Examples of transactions that constitute a settlement include (a) making lump-sum cash payments to plan participants in exchange for their rights to receive specified benefits and (b) purchasing nonparticipating annuity contracts to cover vested benefits. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 88 -Paragraph 3 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 106 -Paragraph 518 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 87 -Paragraph 264 Reference 4: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h false 17 Amortization of transition obligation 4 us-gaap_DefinedBenefitPlanAmortizationOfTransitionObligationsAssets us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false true false false 500000 0.5 true false false 11 false true false false 500000 0.5 true false false 12 false true false false 1400000 1.4 true false false 13 false true false false 1400000 1.4 true false false 14 false true false false 1900000 1.9 true false false 15 false true false false 1900000 1.9 true false false xbrli:monetaryItemType monetary The amount of the transition obligation or asset recognized in net periodic benefit cost. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h false 18 Amortization of losses 4 us-gaap_DefinedBenefitPlanAmortizationOfGainsLosses us-gaap true credit duration No definition available. false false false false false false false false false false true negated false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false true false false 100000 0.1 true false false 11 false true false false 200000 0.2 true false false 12 false true false false 500000 0.5 true false false 13 false true false false 700000 0.7 true false false 14 false true false false 700000 0.7 true false false 15 false true false false 700000 0.7 true false false xbrli:monetaryItemType monetary The amount of gains or losses recognized in net periodic benefit cost Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h false 19 Accretion of regulatory liability 4 str_AccretionOfRegulatoryLiability str false debit duration A periodic charge recognizing amounts collected in rates in excess of actual postretirement expenses. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false true false false 200000 0.2 true false false 11 false true false false 200000 0.2 true false false 12 false true false false 600000 0.6 true false false 13 false true false false 600000 0.6 true false false 14 false true false false 800000 0.8 true false false 15 false true false false 800000 0.8 true false false xbrli:monetaryItemType monetary A periodic charge recognizing amounts collected in rates in excess of actual postretirement expenses. No authoritative reference available. false 20 Pension/postretirement benefits expense 4 us-gaap_DefinedBenefitPlanNetPeriodicBenefitCost us-gaap true debit duration No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false true false false 7400000 7.4 true false false 5 false true false false 7000000 7.0 true false false 6 false true false false 19700000 19.7 true false false 7 false true false false 17700000 17.7 true false false 8 false true false false 26000000 26.0 true false false 9 false true false false 23900000 23.9 true false false 10 false true false false 1300000 1.3 true false false 11 false true false false 1600000 1.6 true false false 12 false true false false 4600000 4.6 true false false 13 false true false false 5100000 5.1 true false false 14 false true false false 6200000 6.2 true false false 15 false true false false 6100000 6.1 true false false xbrli:monetaryItemType monetary The total amount of net periodic benefit cost for defined benefit plans for the period. Periodic benefit costs include the following components: service cost, interest cost, expected return on plan assets, gain or loss, prior service cost or credit, transition asset or obligation, and gain or loss due to settlements or curtailments). Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 132R -Paragraph 5 -Subparagraph h false 21 Estimated postretirement benefits expense for current fiscal year, before accretion of regulatory liability 1 str_DefinedBenefitPostretirementBenefitsPlanEstimatedExpenseInCurrentFiscalYear str false debit instant The employer's best estimate of postretirement benefits expense for the current fiscal year, before accretion of regulatory... false false false false false false false false false false false terselabel false 1 false true false false 5000000 5.0 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary The employer's best estimate of postretirement benefits expense for the current fiscal year, before accretion of regulatory liability. No authoritative reference available. false 22 Estimated accretion of regulatory liability for current fiscal year 1 str_EstimatedAccretionOfRegulatoryLiabilityInCurrentFiscalYear str false credit instant The employer's best estimate of accretion of regulatory liability for the current fiscal year. false false false false false false false false false false false terselabel false 1 false true false false 800000 0.8 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary The employer's best estimate of accretion of regulatory liability for the current fiscal year. No authoritative reference available. false 23 Reduction in accumulated postretirement benefit obligation due to Medicare Part D benefit 1 us-gaap_PrescriptionDrugBenefitReductionInAccumulatedPostretirementBenefitObligationForSubsidy us-gaap true debit instant No definition available. false false false false false false false false false false false false 1 false false false false 0 0 false false false 2 false false false false 0 0 false false false 3 false true false false 2000000 2.0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary Amount of the reduction in the accumulated postretirement benefit obligation for the government subsidy related to prescription drug benefits attributed to past service. Disclosure relates to the first period in which an employer includes the effects of the subsidy in measuring the accumulated postretirement benefit obligation and net periodic postretirement benefit cost. Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name FASB Staff Position (FSP) -Number FAS106-2 -Paragraph 21 -Subparagraph a false 24 Cumulative Medicare Part D benefit 1 str_CumulativePrescriptionDrugBenefitReductionInAccumulatedPostretirementBenefitObligationForSubsidy str false debit instant Amount of the cumulative drug benefit subsidy related to prescription drug benefits attributed to past service. false false false false false false false false false false false terselabel false 1 false false false false 0 0 false false false 2 false true false false 4000000 4.0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary Amount of the cumulative drug benefit subsidy related to prescription drug benefits attributed to past service. No authoritative reference available. false 25 Amount of yearly amortization of Medicare Part D benefit 1 str_PrescriptionDrugBenefitAnnualAmortizationEffectOfSubsidyOnAnnualPostretirementBenefitCost str false debit instant Annual amortization amount of the Medicare Part D subsidy benefit, which reduces net periodic postretirement benefit cost... false false false false false false false false false false false terselabel false 1 true true false false 300000 0.3 false false false 2 false false false false 0 0 false false false 3 false false false false 0 0 false false false 4 false false false false 0 0 true false false 5 false false false false 0 0 true false false 6 false false false false 0 0 true false false 7 false false false false 0 0 true false false 8 false false false false 0 0 true false false 9 false false false false 0 0 true false false 10 false false false false 0 0 true false false 11 false false false false 0 0 true false false 12 false false false false 0 0 true false false 13 false false false false 0 0 true false false 14 false false false false 0 0 true false false 15 false false false false 0 0 true false false xbrli:monetaryItemType monetary Annual amortization amount of the Medicare Part D subsidy benefit, which reduces net periodic postretirement benefit cost through a decrease in the amortization of the unrecognized net loss. No authoritative reference available. false 15 22 false HundredThousands UnKnown UnKnown false true