2.2.0.7 false CONSOLIDATED STATEMENTS OF INCOME (USD $) 00100 - Statement - CONSOLIDATED STATEMENTS OF INCOME true false In Millions, except Per Share data false false 1 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Unit12 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 2 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit12 Standard http://www.xbrl.org/2003/instance shares xbrli 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ false 3 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 Unit12 Standard http://www.xbrl.org/2003/instance shares xbrli 0 $ false 4 USD false false Unit1 Standard http://www.xbrl.org/2003/iso4217 USD iso4217 0 Unit12 Standard http://www.xbrl.org/2003/instance shares xbrli 0 Unit13 Divide http://www.xbrl.org/2003/iso4217 USD iso4217 http://www.xbrl.org/2003/instance shares xbrli 0 $ 2 CONSOLIDATED STATEMENTS OF INCOME 0 us-gaap_IncomeStatementAbstract 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 false false false xbrli:stringItemType string No definition available. false 3 Operating revenues 1 us-gaap_Revenues 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 1043700000 1043.7 false false false 2 true true false false 793700000 793.7 false false false 3 true true false false 3038300000 3038.3 false false false 4 true true false false 2565700000 2565.7 false false false xbrli:monetaryItemType monetary Aggregate revenue recognized during the period (derived from goods sold, services rendered, insurance premiums, or other activities that constitute an entity's earning process). For financial services companies, also includes investment and interest income, and sales and trading gains. 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No authoritative reference available. false 8 Gain on sale of Virginia distribution business 2 us-gaap_DisposalGroupNotDiscontinuedOperationGainLossOnDisposal us-gaap true credit duration No definition available. false false false false false false false false false false true negated false 1 false true false false 0 0 false false false 2 false true false false 0 0 false false false 3 false true false false -45100000 -45.1 false false false 4 false true false false 0 0 false false false xbrli:monetaryItemType monetary The gain (loss) resulting from the sale of a disposal group that is not a discontinued operation. It is included in income from continuing operations before income taxes in the income statement. 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No authoritative reference available. false 12 Total operating expenses 2 us-gaap_CostsAndExpenses us-gaap true debit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 791100000 791.1 false false false 2 false true false false 587800000 587.8 false false false 3 false true false false 2296600000 2296.6 false false false 4 false true false false 1890900000 1890.9 false false false xbrli:monetaryItemType monetary Total costs of sales and operating expenses for the period. No authoritative reference available. true 13 Operating income 1 us-gaap_OperatingIncomeLoss us-gaap true credit duration No definition available. false false false false false false false false false false false totallabel false 1 false true false false 252600000 252.6 false false false 2 false true false false 205900000 205.9 false false false 3 false true false false 741700000 741.7 false false false 4 false true false false 674800000 674.8 false false false xbrli:monetaryItemType monetary The net result for the period of deducting operating expenses from operating revenues. No authoritative reference available. true 14 Other income (expense), net 1 us-gaap_OtherNonoperatingIncomeExpense us-gaap true credit duration No definition available. false false false false false false false false false false false false 1 false true false false 4400000 4.4 false false false 2 false true false false 1900000 1.9 false false false 3 false true false false 9700000 9.7 false false false 4 false true false false 6100000 6.1 false false false xbrli:monetaryItemType monetary The net amount of other nonoperating income and expense, which does not qualify for separate disclosure on the income statement under materiality guidelines. 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If the entity does not present consolidated financial statements, the amount of profit or loss for the period, net of income taxes. 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