Shareholders' Equity (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Shareholders' Equity Activity Summarization [Line Items]
Effect of early adoption of income tax consequences of intra-entity transfer of assets other than inventory	[1]		$ 384
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[2]	$ (30)
Shareholders' equity activity [Roll Forward]
Balance at beginning of period		8,349	9,448
Payments of dividends to shareholders		(158)	(156)
Stock plans		139	120
Other		(14)	(9)
Comprehensive income (loss)		45	(30)
Balance at end of period		8,391	8,989
Company shareholders' equity
Shareholders' Equity Activity Summarization [Line Items]
Effect of early adoption of income tax consequences of intra-entity transfer of assets other than inventory	[1]		384
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[2]	(30)
Shareholders' equity activity [Roll Forward]
Balance at beginning of period		8,322	9,409
Payments of dividends to shareholders		(158)	(156)
Stock plans		139	120
Other		(12)	(8)
Comprehensive income (loss)		44	(30)
Balance at end of period		8,365	8,951
Noncontrolling interest in consolidated subsidiaries
Shareholders' Equity Activity Summarization [Line Items]
Effect of early adoption of income tax consequences of intra-entity transfer of assets other than inventory	[1]		0
New Accounting Pronouncement or Change in Accounting Principle, Cumulative Effect of Change on Equity or Net Assets	[2]	0
Shareholders' equity activity [Roll Forward]
Balance at beginning of period		27	39
Payments of dividends to shareholders		0	0
Stock plans		0	0
Other		(2)	(1)
Comprehensive income (loss)		1	0
Balance at end of period		$ 26	$ 38

[1] Represents a cumulative-effect adjustment to retained earnings upon our adoption of a new accounting standards update on the income tax consequences of intra-entity transfers of assets other than inventory which was effective January 1, 2017.

[2] Represents a cumulative-effect adjustment to retained earnings upon our adoption of new accounting standards effective January 1, 2018. See Note 9 for further information on the adoption of the new revenue recognition standard.