Taxes (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
U.S. federal
Current	$ (382)	$ (623)	$ (817)
Deferred	(2,561)	(1,558)	(580)
State and local
Current	(97)	(15)	(187)
Deferred	66	(121)	(109)
Total United States	(2,974)	(2,317)	(1,693)
International
Current	3,634	2,744	2,997
Deferred	(708)	(2,156)	(1,172)
Total International	2,926	588	1,825
Total income tax expense (benefit)	$ (48)	$ (1,729)	$ 132