Goodwill (Schedule of Goodwill) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015
Goodwill [Roll Forward]
Balance at December 31, 2014	$ 3,011
Foreign currency translation adjustments	(106)
Balance at March 31, 2015	2,905
North America [Member]
Goodwill [Roll Forward]
Balance at December 31, 2014	1,896
Foreign currency translation adjustments	(73)
Balance at March 31, 2015	1,823
MENA/ Asia Pacific [Member]
Goodwill [Roll Forward]
Balance at December 31, 2014	195
Foreign currency translation adjustments	(3)
Balance at March 31, 2015	192
Europe/ SSA/ Russia [Member]
Goodwill [Roll Forward]
Balance at December 31, 2014	623
Foreign currency translation adjustments	(25)
Balance at March 31, 2015	598
Latin America [Member]
Goodwill [Roll Forward]
Balance at December 31, 2014	297
Foreign currency translation adjustments	(5)
Balance at March 31, 2015	292
Land Drilling Rigs [Member]
Goodwill [Roll Forward]
Balance at December 31, 2014	0
Foreign currency translation adjustments	$ 0