Acquisitions, Divestitures, Intangible Assets And Goodwill (Narrative) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Acquisitions Divestitures Intangible Assets And Goodwill [Line Items]
Acquisition of business, aggregate value	$ 1,560	$ 233	$ 811
Transaction-related costs	17
Amortization expense	238	224	218
Number of businesses acquired	6
Other Income [Member]
Acquisitions Divestitures Intangible Assets And Goodwill [Line Items]
Pretax gain on sale of detection systems reported in other income	$ 38