Unaudited Selected Quarterly Data (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2010	Sep. 30, 2010	Jun. 30, 2010	Mar. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Unaudited Selected Quarterly Data (Table Amounts) [Abstract]
Sales and services revenues	$ 6,506	$ 6,612	$ 6,560	$ 6,734	$ 6,903	$ 7,071	$ 7,255	$ 6,914	$ 26,412	$ 28,143	$ 27,650
Operating income	799	825	841	811	675	723	749	680	3,276	2,827	2,274
Earnings from continuing operations	550	520	520	496	306	448	740	410	2,086	1,904	1,434
Net earnings	548	520	520	530	376	497	711	469	2,118	2,053	1,686
Basic earnings per share from continuing operations	$ 2.13	$ 1.89	$ 1.84	$ 1.70	$ 1.05	$ 1.53	$ 2.47	$ 1.36	$ 7.54	$ 6.41	$ 4.49
Basic earnings per share	$ 2.12	$ 1.89	$ 1.84	$ 1.82	$ 1.29	$ 1.69	$ 2.37	$ 1.55	$ 7.65	$ 6.91	$ 5.28
Diluted earnings per share from continuing operations	$ 2.09	$ 1.86	$ 1.81	$ 1.67	$ 1.03	$ 1.51	$ 2.44	$ 1.34	$ 7.41	$ 6.32	$ 4.44
Diluted earnings per share	$ 2.09	$ 1.86	$ 1.81	$ 1.79	$ 1.27	$ 1.67	$ 2.34	$ 1.53	$ 7.52	$ 6.82	$ 5.21
Weighted-average common shares outstanding, in millions	258.2	274.9	282.6	291.8	291.8	293.5	299.6	302.5	276.8	296.9	319.2
Weighted-average diluted shares outstanding, in millions	262.7	279.3	287.2	296.9	296.9	297.6	303.8	306.1	281.6	301.1	323.3
Unaudited Selected Quarterly Data (Amounts in Paragraphs)
Contribution to the company's pension plans	500				360
Charge on debt redemption					229					(229)
No of common stock shares repurchased	11.8				1.9
Amount paid for common stock repurchased	$ 649				$ 118