Investments (Tables)

12 Months Ended

Dec. 31, 2019

Investments, Debt and Equity Securities [Abstract]

Amortized Cost, Gross Unrealized Gains and Losses, Fair Values of Investments

The amortized cost, gross unrealized gains, gross unrealized losses, and fair values of our AFS investments as of December 31, 2019 and 2018 are presented below:

	December 31, 2019								December 31, 2018
(in millions)	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Fair Value
Asset-backed securities	$	30	$	—	$	—	$	30	$	33	$	—	$	—	$	33
Corporate bonds	123		1		—		124		99		—		—		99
U.S. government agencies and government-sponsored agencies	14		—		—		14		7		—		—		7
U.S. treasuries	163		—		—		163		46		—		—		46
Exchange traded fund	—		—		—		—		1		—		—		1
Certificates of deposit	1		—		—		1		—		—		—		—
Other debt securities	10		—		—		10		9		—		—		9
Total	$	341	$	1	$	—	$	342	$	195	$	—	$	—	$	195

Fair Value of Debt Investments by Contractual Maturity

The fair value of debt investments by contractual maturity are shown below:

(in millions)	December 31, 2019		December 31, 2018
One year or less	$	80	$	59
Over one year through five years	237		120
Over five years through ten years	8		3
Over ten years	17		12
Total fair value	$	342	$	194

Proceeds from Available-for-sale Securities

The gross proceeds from sales and maturities of AFS securities for the years ended December 31, 2019, 2018, and 2017 are shown below. We had immaterial realized gains and losses from sales of investments for the years ended December 31, 2019, 2018, and 2017.

	Year Ended December 31,
(in millions)	2019		2018		2017
Gross proceeds from sales	$	76	$	54	$	—
Gross proceeds from maturities	83		47		14
Total	$	159	$	101	$	14