Acquisitions And Divestitures (Narrative) (Details) $ / shares in Units, $ in Millions	3 Months Ended								12 Months Ended
	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Sep. 30, 2015 USD ($) $ / shares	Jun. 30, 2015 USD ($)	Mar. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($)	Sep. 30, 2016 USD ($)	Sep. 30, 2015 USD ($) $ / shares	Sep. 30, 2014 USD ($)	Jan. 29, 2015 USD ($)	Dec. 31, 2013 USD ($)	Nov. 22, 2013 USD ($)	Sep. 30, 2013 USD ($)
Business Acquisition [Line Items]
Purchases of businesses, net of cash acquired									$ 132	$ 324	$ 610
Net sales	$ 3,932	$ 3,674	$ 3,579	$ 3,337	$ 4,204	$ 4,085	$ 3,934	$ 4,026	14,522	16,249	17,733
Goodwill	3,909				3,847				3,909	3,847	4,238
Other current assets	669				724				669	724
Intangible assets, net (excluding goodwill)	902				938				902	938
Current assets held-for-sale	2,200				2,136				2,200	2,136
Gain on divestiture of business, after tax					$ 83				0	611	0
Disposal gain impact on diluted earnings per share | $ / shares					$ 0.13
Pretax earnings									2,316	3,807	3,191
Current liabilities held-for-sale	1,601				$ 1,566				1,601	1,566
Gains on divestitures of businesses									0	1,039	0
Increase (decrease) in deferred tax asset											130
Net earnings									1,664	2,733	2,184
Liabilities held-for-sale, accrued expenses	2,126				2,058				2,126	2,058
Common stock repurchased during the period	12,831				12,257				12,831	12,257					$ 600
Noncontrolling interests in subsidiaries [Member]
Business Acquisition [Line Items]
Purchase of noncontrolling interests									$ 0	$ 0	101
Parent [Member]
Business Acquisition [Line Items]
Purchase of noncontrolling interests											$ 343
Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of businesses acquired									6	8	4
Purchases of businesses, net of cash acquired									$ 132	$ 324	$ 104
Net sales									51	115	55
Goodwill	83				178				83	178
Goodwill, expected tax deductible amount	27				42				27	42
Intangible assets, net (excluding goodwill)	50				128				$ 50	$ 128
Intangible assets, weighted average useful life									9 years	10 years
Pentair's Valves & Controls [Member]
Business Acquisition [Line Items]
Purchases of businesses, net of cash acquired									$ 3,150
Net sales									1,600
Virgo and Enardo [Member]
Business Acquisition [Line Items]
Purchases of businesses, net of cash acquired											506
Net sales											321
Goodwill											323
Intangible assets, net (excluding goodwill)											178
Intangible assets, weighted average useful life										12 years
Debt assumed in acquisition											$ 76
Percentage of interest acquired											100.00%
Appleton Group [Member]
Business Acquisition [Line Items]
Net sales											$ 542
Payments to acquire business, net of cash acquired											$ 574
Percentage of noncontrolling interest acquired											44.50%
Process Management [Member]
Business Acquisition [Line Items]
Goodwill	2,810				2,790				$ 2,810	$ 2,790	$ 2,701
Process Management [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of businesses acquired									4	7
Climate Technologies [Member]
Business Acquisition [Line Items]
Goodwill	532				492				$ 532	$ 492	500
Climate Technologies [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of businesses acquired									2
Commercial & Residential Solutions [Member]
Business Acquisition [Line Items]
Goodwill	$ 196				196				$ 196	$ 196	430
Commercial & Residential Solutions [Member] | Series of Individually Immaterial Business Acquisitions [Member]
Business Acquisition [Line Items]
Number of businesses acquired										1
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Connectivity Solutions [Member]
Business Acquisition [Line Items]
Net sales											63
Pretax earnings											3
Proceeds from divestitures of businesses											99
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Power Transmission Solutions [Member]
Business Acquisition [Line Items]
Net sales										$ 189
Current assets held-for-sale												$ 182
Gain on divestiture of business, after tax							$ 528			$ 532
Disposal gain impact on diluted earnings per share | $ / shares							$ 0.77			$ 0.78
Pretax earnings										$ 21
Other noncurrent assets												374
Current liabilities held-for-sale												56
Deferred taxes and other noncurrent liabilities												$ 41
Proceeds from divestitures of businesses										1,400
Gains on divestitures of businesses										939
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | InterMetro [Member]
Business Acquisition [Line Items]
Net sales										288
Current assets held-for-sale					62					62
Gain on divestiture of business, after tax										$ 79
Disposal gain impact on diluted earnings per share | $ / shares										$ 0.12
Pretax earnings										$ 42
Other noncurrent assets					292					292
Current liabilities held-for-sale					34					34
Deferred taxes and other noncurrent liabilities					$ 9					9
Proceeds from divestitures of businesses										411
Gains on divestitures of businesses										$ 100
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Artesyn (Embedded Computing and Power) [Member]
Business Acquisition [Line Items]
Net sales											146
Other current assets														$ 367
Proceeds from divestitures of businesses											264
Percentage of controlling interest sold														51.00%
Tax benefit (detriment) from divestiture of business											20
Other noncurrent assets, including property, plant, equipment, net and goodwill														$ 212
Net earnings											$ (9)
Pre-tax foreign cash repatriated													$ 376
Liabilities held-for-sale, accrued expenses														255
After-tax foreign cash repatriated													$ 308
Disposal Group, Disposed of by Sale, Not Discontinued Operations [Member] | Artesyn (Embedded Computing and Power) [Member] | Artesyn (Embedded Computing and Power) [Member]
Business Acquisition [Line Items]
Fair value of equity method investment														$ 60