Loss Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended	6 Months Ended
Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Numerator for loss per share, basic and diluted
Net loss attributable to controlling interest	$ (103)	$ (497)	$ (202)	$ (889)
Denominator for loss per share, basic and diluted
Weighted-average shares outstanding (in shares)	620.0	614.0	618.0	614.0
Effect of share-based awards (in shares)	1.0	1.0	1.0	1.0
Weighted-average shares for per share calculation	621.0	615.0	619.0	615.0
Loss per share, basic and diluted (in dollars per share)	$ (0.17)	$ (0.81)	$ (0.33)	$ (1.45)
Share-based awards
Denominator for loss per share, basic and diluted
Securities excluded from earnings per share calculation (in shares)	13.3	14.8	12.9	13.0
Convertible debt
Denominator for loss per share, basic and diluted
Securities excluded from earnings per share calculation (in shares)	108.0	84.0	101.0	84.0
0.50% Exchangeable Senior Bonds due January 2023
Denominator for loss per share, basic and diluted
Debt instrument interest rate stated percentage	0.50%	0.50%	0.50%	0.50%
2.50% Senior Guaranteed Exchangeable Bonds due January 2027
Denominator for loss per share, basic and diluted
Debt instrument interest rate stated percentage	2.50%		2.50%
4.00% Senior Guaranteed Exchangeable Bonds due December 2025
Denominator for loss per share, basic and diluted
Debt instrument interest rate stated percentage	4.00%		4.00%

Securities (including those issuable pursuant to contingent stock agreements) that could potentially dilute basic earnings per share (EPS) or earnings per unit (EPU) in the future that were not included in the computation of diluted EPS or EPU because to do so would increase EPS or EPU amounts or decrease loss per share or unit amounts for the period presented.

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Contractual interest rate for funds borrowed, under the debt agreement.

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