Investments - (Tables)

12 Months Ended

Dec. 31, 2021

Investments, Debt and Equity Securities [Abstract]

Amortized cost, gross unrealized gains, gross unrealized losses and estimated fair values of available-for-sale investments by type of security

The amortized cost, gross unrealized gains, gross unrealized losses and fair values of interest-bearing securities, all of which are considered available-for-sale, by type of security were as follows (in millions):

Types of securities as of December 31, 2021	Amortized cost		Gross unrealized gains		Gross unrealized losses		Fair values
U.S. Treasury notes	$	47	$	—	$	—	$	47
U.S. Treasury bills	1,400		—		—		1,400
Money market mutual funds	5,856		—		—		5,856
Other short-term interest-bearing securities	1		—		—		1
Total available-for-sale investments	$	7,304	$	—	$	—	$	7,304

Types of securities as of December 31, 2020	Amortized cost		Gross unrealized gains		Gross unrealized losses		Fair values
U.S. Treasury notes	$	129	$	1	$	—	$	130
U.S. Treasury bills	4,948		—		—		4,948
Money market mutual funds	4,765		—		—		4,765
Other short-term interest-bearing securities	2		—		—		2
Total available-for-sale investments	$	9,844	$	1	$	—	$	9,845

Fair values of available-for-sale investments by classification in the Consolidated Balance Sheets

The fair values of available-for-sale investments by location in the Consolidated Balance Sheets were as follows (in millions):

	December 31,
Consolidated Balance Sheets locations	2021		2020
Cash and cash equivalents	$	7,256	$	5,464
Marketable securities	48		4,381
Total available-for-sale investments	$	7,304	$	9,845

Fair values of available-for-sale interest-bearing security investments by contractual maturity

The fair values of available-for-sale investments by contractual maturity were as follows (in millions):

	December 31,
Contractual maturities	2021		2020
Maturing in one year or less	$	7,304	$	9,795
Maturing after one year through three years	—		50
Total available-for-sale investments	$	7,304	$	9,845