Investments and Advances (Details 1) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Affiliates [Member]
Schedule of Investments [Line Items]
Total revenues	$ 71,389	$ 123,003	$ 131,875
Income before income tax expense	13,129	20,609	24,075
Net income attributable to affiliates	10,649	14,758	15,594
Current assets	27,162	35,662	39,713
Noncurrent assets	71,650	70,817	68,593
Current liabilities	20,559	25,308	29,642
Noncurrent liabilities	18,560	17,983	19,442
Total affiliates' net equity	59,693	63,188	59,222
Parent [Member]
Schedule of Investments [Line Items]
Total revenues	33,492	58,937	63,101
Income before income tax expense	6,279	9,968	11,108
Net income attributable to affiliates	4,691	7,237	7,845
Current assets	10,657	13,465	15,156
Noncurrent assets	26,607	26,053	25,059
Current liabilities	7,351	9,588	11,587
Noncurrent liabilities	3,909	4,211	4,559
Total affiliates' net equity	$ 26,004	$ 25,719	$ 24,069