Revenue - Changes in Contract Liabilities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Contract Liabilities:
Balance at beginning of period	$ 500	$ 520
Unearned revenue from cash received during the period	469	578
Revenue recognized related to contract liability balance	(424)	(598)
Balance at end of period	$ 545	$ 500