Supplemental Cash Flow Information (Details) - USD ($) $ in Millions	1 Months Ended		6 Months Ended
	Jul. 31, 2015	Jul. 31, 2014	Jun. 30, 2015	Jun. 30, 2014
Decrease (increase) in current assets:
Receivables, net			$ 77	$ 837
Inventories			(19)	(721)
Income taxes receivable			79	(16)
Prepaid expenses and other			7	11
Increase (decrease) in current liabilities:
Accounts payable			575	(707)
Accrued expenses			(75)	12
Taxes other than income taxes			15	(71)
Income taxes payable			(44)	(369)
Changes in current assets and current liabilities			615	(1,024)
Cash Flows Related to Interest and Income Taxes
Interest paid in excess of amount capitalized			202	197
Income taxes paid, net			1,079	1,054
Supplemental Cash Flow Elements (Textual)
Treasury stock purchased but settled in subsequent quarter			$ 41	$ 104
Stock purchases, in shares		2,000,000
Subsequent Event [Member]
Supplemental Cash Flow Elements (Textual)
Stock purchases, in shares	675,000