Indebtedness - Schedule of Notes Maturity (Details) - Unsecured Senior Notes $ in Millions	Dec. 31, 2019 USD ($)
Debt Instrument [Line Items]
2020	$ 0
2021	492
2022	206
2023	950
2024	0
Thereafter	750
Total unsecured senior notes principal amount	$ 2,398

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

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