Contractual Guarantees, Litigation, Investigations, And Insurance (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended	44 Months Ended
	Sep. 27, 2013 insurer	Sep. 27, 2013 Clark County Nevada Against Jacobs Engineering Group, Inc. [Member]	Sep. 28, 2012 Clark County Nevada Against Jacobs Engineering Group, Inc. [Member] arbitrator	Jan. 20, 2010 Clark County Nevada Against Jacobs Engineering Group, Inc. [Member] subsidiary
Loss Contingencies [Line Items]
Minimum number of insurers with possible inability to fulfill insurance obligations	1
Number Of subsidiaries (in subsidiaries)				2
Third party payment of settlement and awards (more than 60 million)		$ 60
Number Of arbitrators (in arbitrators)			3