Debt (Tables)

9 Months Ended

Sep. 30, 2020

Debt Disclosure [Abstract]

Summary of debt

A summary of our outstanding unsecured senior notes is as follows (amounts in millions):

				At September 30, 2020			At December 31, 2019
Unsecured Senior Notes	Interest Rate	Semi-Annual Interest Payments Due On	Maturity	Principal		Fair Value (Level 2)	Principal		Fair Value (Level 2)
2021 Notes	2.30%	Mar. 15 & Sept. 15	Sept. 2021	$	—	—	$	650	$	653
2022 Notes	2.60%	Jun. 15 & Dec. 15	Jun. 2022	—		—	400		405
2026 Notes	3.40%	Mar. 15 & Sept. 15	Sept. 2026	850		968	850		893
2027 Notes	3.40%	Jun. 15 & Dec. 15	Jun. 2027	400		453	400		417
2030 Notes	1.35%	Mar. 15 & Sept. 15	Sept. 2030	500		488	—		—
2047 Notes	4.50%	Jun. 15 & Dec. 15	Jun. 2047	400		508	400		456
2050 Notes	2.50%	Mar. 15 & Sept. 15	Sept. 2050	1,500		1,386	—		—
Total gross long-term debt				$	3,650		$	2,700
Unamortized discount and deferred financing costs				(46)			(25)
Total net carrying amount				$	3,604		$	2,675