Shareholders' Equity (Details) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010	Dec. 31, 2010
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			$ 10,387	$ 8,757
Transactions with shareholders			299	111
Treasury shares issued for acquisition of Boots & Coots, Inc.				105
Shares repurchased				(114)
Comprehensive income:
Net income	685	545	1,937	1,235
Other comprehensive income				4
Total comprehensive income	685	545	1,937	1,239
Payments of dividends to shareholders			(247)	(245)
Balance at end of period	12,376	9,853	12,376	9,853
Summary of comprehensive income [Abstract]
Net income	685	545	1,937	1,235
Other comprehensive income (loss)				4
Total comprehensive income	685	545	1,937	1,239
Comprehensive income attributable to noncontrolling interest	2	1
Comprehensive income attributable to company	683	544
Accumulated other comprehensive loss [Abstract]
Defined benefit and other postretirement liability adjustments	(175)		(175)		(175)
Cumulative translation adjustments	(66)		(66)		(66)
Unrealized gains on investments	1		1		1
Total accumulated other comprehensive loss	(240)		(240)		(240)
Company shareholders' equity [Member]
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			10,373	8,728
Transactions with shareholders			299	131
Treasury shares issued for acquisition of Boots & Coots, Inc.				105
Shares repurchased				(114)
Comprehensive income:
Net income			1,933	1,230
Other comprehensive income				5
Total comprehensive income			1,933	1,235
Payments of dividends to shareholders			(247)	(245)
Balance at end of period	12,358	9,840	12,358	9,840
Summary of comprehensive income [Abstract]
Net income			1,933	1,230
Other comprehensive income (loss)				5
Total comprehensive income			1,933	1,235
Noncontrolling interest in consolidated subsidiaries [Member]
Shareholders' equity activity [Roll Forward]
Balance at beginning of period			14	29
Transactions with shareholders			0	(20)
Treasury shares issued for acquisition of Boots & Coots, Inc.				0
Shares repurchased				0
Comprehensive income:
Net income			4	5
Other comprehensive income				(1)
Total comprehensive income			4	4
Payments of dividends to shareholders			0	0
Balance at end of period	18	13	18	13
Summary of comprehensive income [Abstract]
Net income			4	5
Other comprehensive income (loss)				(1)
Total comprehensive income			$ 4	$ 4