Debt - Schedule of 6.5% Convertible Senior Notes (Details) - USD ($)	12 Months Ended
Dec. 31, 2020	Jun. 30, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt, net of current maturities	$ 29,324,000,000		$ 20,896,000,000
Senior Notes 6.50% Due 2025 \| Senior Notes
Debt Instrument [Line Items]
Aggregate principal issued	1,000,000,000	$ 1,000,000,000.0
Unamortized debt discount	(417,000,000)
Long-term debt, net of current maturities	583,000,000
Additional paid-in capital	$ 415,000,000

Adjustment to additional paid in capital resulting from the recognition of convertible debt instruments as two separate components - a debt component and an equity component. This bifurcation may result in a basis difference associated with the liability component that represents a temporary difference for purposes of applying accounting for income taxes. The initial recognition of deferred taxes for the tax effect of that temporary difference is as an adjustment to additional paid in capital.

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Face (par) amount of debt instrument at time of issuance.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

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