COMPREHENSIVE INCOME (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 25, 2011	Sep. 26, 2010	Sep. 25, 2011	Sep. 26, 2010
Comprehensive income (loss)
Net income	$ 472	$ 309	$ 1,374	$ 749
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities	1	3	1	4
Unrealized gain (loss) on derivatives	(19)	7	(31)
Foreign currency translation adjustments	(177)	87	(123)	26
Change in pensions and other postretirement defined benefit plans	7	8	40	10
Total other comprehensive income (loss)	(188)	105	(113)	40
Total comprehensive income	284	414	1,261	789
Total Cummins Inc. Shareholders' Equity
Comprehensive income (loss)
Net income	452	283	1,300	678
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities		1		2
Unrealized gain (loss) on derivatives	(19)	7	(31)
Foreign currency translation adjustments	(154)	80	(100)	19
Change in pensions and other postretirement defined benefit plans	7	8	40	10
Total other comprehensive income (loss)	(166)	96	(91)	31
Total comprehensive income	286	379	1,209	709
Noncontrolling Interests
Comprehensive income (loss)
Net income	20	26	74	71
Other comprehensive income (loss), net of tax
Unrealized gain (loss) on marketable securities	1	2	1	2
Foreign currency translation adjustments	(23)	7	(23)	7
Total other comprehensive income (loss)	(22)	9	(22)	9
Total comprehensive income	$ (2)	$ 35	$ 52	$ 80