Accounting Policies - New Accounting Pronouncements (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
New Accounting Pronouncements or Change in Accounting Principle
Income tax provision (benefit)	$ 766	$ 604	$ 1,338	$ 1,350
Condensed Consolidated Statements of Cash Flows
Cash paid to other suppliers and employees			(7,000)	(7,019)
Net cash provided by operating activities			5,532	4,086
Net cash used in financing activities			(5,635)	(4,189)
Reconciliation of net income to net cash provided by operating activities:
Accrued expenses			1,345	555
Condensed Consolidated Statements of Income
Operating expenses	4,818	4,658	9,605	9,217
Operating profit	2,117	2,357	3,910	4,542
Other expense	7	7	14	16
Previously Reported
Condensed Consolidated Statements of Cash Flows
Cash paid to other suppliers and employees				(7,082)
Net cash provided by operating activities				4,023
Excess tax benefits from stock-based compensation				63
Net cash used in financing activities				(4,126)
Reconciliation of net income to net cash provided by operating activities:
Accrued expenses				492
Condensed Consolidated Statements of Income
Operating expenses		4,665		9,233
Operating profit		2,350		4,526
Adjustment
Condensed Consolidated Statements of Cash Flows
Cash paid to other suppliers and employees				63
Net cash provided by operating activities				63
Excess tax benefits from stock-based compensation				(63)
Net cash used in financing activities				(63)
Reconciliation of net income to net cash provided by operating activities:
Accrued expenses				63
Condensed Consolidated Statements of Income
Operating expenses		(7)		(16)
Operating profit		7		16
Other expense		$ 7		$ 16
ASU 2016-09 | Previously Reported
New Accounting Pronouncements or Change in Accounting Principle
Income tax provision (benefit)	$ (14)		$ (33)