Summary of Significant Accounting Policies (Tables)

12 Months Ended

Dec. 31, 2019

Summary of Significant Accounting Policies [Abstract]

Valuation of Option Grants under Stock Option Plans

	2019				2018				2017
Expected volatility	29.1	-	29.9	%	30.6	-	31.4	%	32.4	-	36.1	%
Weighted-average volatility	29.9%				31.4%				36.1%
Expected dividends	2.36	-	2.95	%	2.22	-	2.66	%	1.98	-	2.28	%
Risk-free rate	1.5	-	2.4	%	2.7	-	3.1	%	2.1	-	2.3	%
Expected term (in years)	7.4	-	7.4		7.4	-	7.4		7.4	-	7.4
Pre-vesting departure rate	0.6	-	0.6	%	0.6	-	0.6	%	0.6	-	0.6	%

Supplemental Disclosure of Cash Flow Information

	Years ended December 31,
	2019		2018		2017
Non-cash transactions:
Accruals for capital expenditures	$	592	$	412	$	584
Cash paid for interest and income taxes:
Interest (1)	$	248	$	205	$	178
Income taxes, net of refunds received	$	474	$	567	$	405

(1)Included in this amount are approximately $54 million, $49 million and $36 million of interest costs that were capitalized as part of property, plant and equipment, net of accumulated depreciation, in 2019, 2018 and 2017, respectively.

Useful Life of Equipment

Asset type	Range of useful life
Computer hardware and software	3 to 7 years
Manufacturing equipment	2 to 15 years
Furniture and fixtures	5 to 10 years
Transportation equipment	3 to 20 years