Income Taxes Items Accounting for Differences between Income Taxes Computed at Federal Statutory Rate and Provision Recorded for Income Taxes (Details) - USD ($) $ in Millions	3 Months Ended																12 Months Ended
	Dec. 31, 2016	[1]	Sep. 30, 2016	[1]	Jun. 30, 2016	[1]	Mar. 31, 2016	[1]	Dec. 31, 2015	[1]	Sep. 30, 2015	[1]	Jun. 30, 2015	[1]	Mar. 31, 2015	[1]	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Tax Disclosure [Abstract]
Income taxes computed at the federal statutory rate																	$ 1,362	$ 549	$ (39)
Effect of:
Impact of foreign tax differential																	(69)	350	136
State taxes, net of federal benefits																	110	37	29
Tax credits																	(119)	(99)	(85)
Nondeductible compensation																	189	149	117
Domestic production activities deduction																	94	44	20
Other, net																	46	8	29
Provision for income taxes, net	$ 414		$ 229		$ 307		$ 475		$ 453		$ 161		$ 266		$ 71		$ 1,425	$ 950	$ 167

[1] The sum of quarterly amounts, including per share amounts, may not equal amounts reported for year-to-date periods. This is due to the effects of rounding and changes in the number of weighted-average shares outstanding for each period.