Long-Term Debt (Details 2) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017
Maturities of Long-term Debt [Abstract]
2019	$ 517
2020	1,127
2021	741
2022	1,505
2023	1,053
Thereafter	9,532
Total principal payments	14,475
Unamortized premium on long-term debt, net of discount	(2)
Debt issuance costs	(73)	$ (82)
Total long-term debt	$ 14,400

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after accumulated amortization, of debt discount (premium).

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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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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing after the fifth fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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Amount of long-term debt payable, sinking fund requirements, and other securities issued that are redeemable by holder at fixed or determinable prices and dates maturing in the third fiscal year following the latest fiscal year. Excludes interim and annual periods when interim periods are reported on a rolling approach, from latest balance sheet date.

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