Debt (Senior Notes - Narrative) (Details) - USD ($)					1 Months Ended	12 Months Ended
	Feb. 26, 2023	Dec. 22, 2021	Sep. 01, 2021	Aug. 30, 2021	Jan. 31, 2015	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Dec. 30, 2022	May 31, 2022	Jan. 06, 2022	Nov. 30, 2021	Apr. 07, 2020	Jul. 31, 2018
Debt Instrument [Line Items]
Loss on Early Extinguishment of Debt						$ (19,000,000)	$ (14,000,000)	$ (93,000,000)
Long-term debt						$ 3,947,000,000	4,392,000,000
Senior Notes
Debt Instrument [Line Items]
Debt repurchased face amount							816,000,000
Loss on Early Extinguishment of Debt		$ (33,000,000)		$ (60,000,000)			(14,000,000)
Repayments of long-term debt				$ 845,000,000			822,000,000
Debt instrument, unamortized discount (premium) and debt issuance costs, net							8,000,000
Debt instrument, purchase accounting, non-cash fair value adjustment			$ 26,000,000
Debt instrument, fee amount							$ 6,000,000
Senior Notes | LIBOR
Debt Instrument [Line Items]
Incremental increase in basis points resulting from downgrades					0.25%
Incremental decrease in basis points resulting from upgrades					0.25%
4.95% Senior Notes due January 2025 | Senior Notes
Debt Instrument [Line Items]
Senior notes, noncurrent					$ 1,000,000,000
Debt Instrument, Interest Rate, Stated Percentage				4.95%	4.95%	4.95%	4.95%				5.95%		6.45%	6.20%
Debt repurchased face amount				$ 167,000,000
4.95% Senior Notes due January 2025 | Senior Notes | Maximum
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage										5.70%
4.10% Senior Notes due March 2022 | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				4.10%			4.10%
Debt repurchased face amount				$ 6,000,000			$ 201,000,000
7.75% Senior Notes due October 2027 | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				7.50%
Debt repurchased face amount				$ 618,000,000
7.75% Senior Notes due October 2027 | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage	7.75%						7.75%
Debt repurchased face amount							$ 19,000,000
Loss on Early Extinguishment of Debt	$ (19,000,000)
Debt instrument, redemption price, percentage of principal amount redeemed	103.875%
Debt instrument, repurchased face amount, unpaid interest	$ 13,000,000
Debt instrument, repurchase amount	450,000,000
Deferred debt issuance cost, writeoff	3,000,000
7.75% Senior Notes due October 2027 | Senior Notes | Funded From Cash On Hand
Debt Instrument [Line Items]
Repayments of senior debt	316,000,000
7.75% Senior Notes due October 2027 | Senior Notes | Funded From Debt Borrowings
Debt Instrument [Line Items]
Repayments of senior debt	$ 134,000,000
8.375% Senior Notes due September 2028 | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						8.375%	8.375%
Debt repurchased face amount							$ 46,000,000
5.375% Senior Notes due March 2030 | Senior Notes
Debt Instrument [Line Items]
Senior notes, noncurrent				$ 1,200,000,000
Debt Instrument, Interest Rate, Stated Percentage				5.375%		5.375%	5.375%
Proceeds from issuance of long-term debt				$ 1,183,000,000
Debt instrument, unamortized discount (premium) and debt issuance costs, net				$ 6,000,000
5.375% Senior Notes due February 2029 | Senior Notes
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			5.375%			5.375%	5.375%
Debt instrument, purchase accounting, non-cash fair value adjustment, percentage			103.766%
Long-term debt			$ 700,000,000									$ 700,000,000
5.375% Senior Notes due February 2029 | Senior Notes | Indigo Merger
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage			5.375%
Senior note assumed in merger agreement			$ 700,000,000
4.75% Senior Notes due February 2032 | Senior Notes
Debt Instrument [Line Items]
Senior notes, noncurrent		1,150,000,000
Debt Instrument, Interest Rate, Stated Percentage						4.75%	4.75%
Proceeds from issuance of long-term debt		1,133,000,000
Debt instrument, unamortized discount (premium) and debt issuance costs, net		1,000,000
Payment to fund tender offers, amount		332,000,000
Tender offer fund, amount		$ 300,000,000
Term Loan Due June 2027 | Term Loan
Debt Instrument [Line Items]
Debt repurchased face amount							$ 550,000,000		$ 546,000,000