Investments (Tables)

12 Months Ended

Dec. 31, 2021

Investments [Abstract]

Amortized Cost and Fair Value of the Trust Investments

		Amortized Cost				Fair Value
	Longest	December 31,
(in millions)	Maturity Date	2021		2020		2021		2020
Stocks	—		*		*	$	1,972	$	1,908
Municipal bonds	2057		875		1,013		1,033		1,218
U.S. government and agency securities	2067		1,095		740		1,212		864
Corporate bonds	2070		386		460		446		550
Short-term investments and receivables/payables1	One-year		199		281		207		293
Total		$	2,555	$	2,494	$	4,870	$	4,833

* Not applicable

1 Short-term investments include $37 million and $138 million of repurchase agreements payable by financial institutions which earn interest, are fully secured by U.S. Treasury securities and mature by January 3, 2022 and January 4, 2021 as of December 31, 2021 and 2020, respectively.

Summary of gains and losses

	December 31,
(in millions)	2021		2020		2019
Gross realized gains	$	339	$	255	$	87
Gross realized losses		(24)		(6)		(2)
Net unrealized gains for equity securities		103		176		343