Consolidated Statement of Comprehensive Income - USD ($) $ in Millions	3 Months Ended	6 Months Ended
Mar. 29, 2019	Mar. 30, 2018	Mar. 29, 2019	Mar. 30, 2018
Statement of Comprehensive Income [Abstract]
Net income	$ 214.0	$ 276.0	$ 498.8	$ 346.4
Other comprehensive income
Fair value of investments	0.1	0.0	0.2	0.0
Other Comprehensive (Income) Loss, Defined Benefit Plan, before Reclassification Adjustment, after Tax	0.5	0.0	0.5	0.0
Foreign currency translation adjustment	0.0	(0.3)	0.0	(0.3)
Comprehensive income	$ 214.6	$ 275.7	$ 499.5	$ 346.1

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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-Name Accounting Standards Codification
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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount after tax and reclassification adjustments, of appreciation (loss) in value of unsold available-for-sale securities. Excludes amounts related to other than temporary impairment (OTTI) loss.

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Amount of tax expense (benefit), after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount, after tax, before reclassification adjustment, of (increase) decrease in accumulated other comprehensive income of defined benefit plan, that has not been recognized in net periodic benefit cost (credit).

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