Share-Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Share-Based Compensation Expense Recognized in Income and the Associated Tax Benefit

Total share-based compensation expense recognized in income and the associated income tax benefit for the years ended December 31 were:

	Millions of Dollars
	2019			2018		2017
Share-based compensation expense	$	169		100		142
Income tax benefit	(53		)	(45	)	(74	)

Stock Option Activity

The following table summarizes our stock option activity from January 1, 2019, to December 31, 2019:

							Millions of Dollars
	Options		Weighted-   Average Exercise Price		Weighted-Average Grant-Date Fair Value		Aggregate Intrinsic Value
Outstanding at January 1, 2019	4,752,808		$	63.11
Granted	830,900		94.97		$	17.58
Forfeited	(553	)	94.85
Exercised	(803,751	)	39.90				$	51
Outstanding at December 31, 2019	4,779,404		$	72.55
Vested at December 31, 2019	3,603,296		$	65.69			$	162
Exercisable at December 31, 2019	3,267,111		$	63.57			$	154

Significant Assumptions Used to Calculate Grant Date Fair Market Values of Options Granted

The following table provides the significant assumptions used to calculate the grant-date fair values of options granted over the years shown below, as calculated using the Black-Scholes-Merton option-pricing model:

	2019		2018	2017
Risk-free interest rate	2.68	%	2.81	2.28
Dividend yield	3.70	%	2.80	2.90
Volatility factor	25.61	%	25.41	26.91
Expected life (years)	7.06		7.18	7.22

Summary of Stock Unit Activity

The following table summarizes our RSU activity from January 1, 2019, to December 31, 2019:

					Millions of Dollars
	Stock Units		Weighted-Average Grant-Date Fair Value		Total Fair Value
Outstanding at January 1, 2019	2,259,829		$	84.52
Granted	1,001,899		95.16
Forfeited	(50,192	)	95.21
Issued	(836,952	)	79.73		$	80
Outstanding at December 31, 2019	2,374,584		$	90.47
Not Vested at December 31, 2019	1,619,720		$	91.04

Summary of Performance Share Program Activity

The following table summarizes our PSU activity from January 1, 2019, to December 31, 2019:

					Millions of Dollars
	Performance Share Units		Weighted-Average Grant-Date  Fair Value		Total Fair Value
Outstanding at January 1, 2019	1,902,502		$	49.52
Granted	287,914		87.42
Forfeited	—		—
Issued	(461,942	)	59.12		$	44
Cash settled	(287,914	)	87.42		25
Outstanding at December 31, 2019	1,440,560		$	46.44
Not Vested at December 31, 2019	73,271		$	69.63