Derivative Instruments - Notional Values and Net Fair Value of Outstanding Contracts (Details) - Foreign Exchange Forward € in Millions, ¥ in Millions, £ in Millions, R in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions	Dec. 31, 2020 GBP (£)	Dec. 31, 2020 EUR (€)	Dec. 31, 2020 CAD ($)	Dec. 31, 2020 AUD ($)	Dec. 31, 2020 JPY (¥)	Dec. 31, 2020 SGD ($)	Dec. 31, 2020 MXN ($)	Dec. 31, 2020 ZAR (R)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 CAD ($)	Dec. 31, 2019 AUD ($)	Dec. 31, 2019 JPY (¥)	Dec. 31, 2019 SGD ($)	Dec. 31, 2019 MXN ($)	Dec. 31, 2019 ZAR (R)	Dec. 31, 2019 USD ($)
Derivative [Line Items]
Net fair value of liabilities of outstanding contracts									$ 3									$ 0
US Dollar
Derivative [Line Items]
Notional balance of outstanding contracts	£ 10	€ 123	$ 0	$ 0	¥ 354	$ 12	$ 36	R 0		£ 14	€ 36	$ 1	$ 42	¥ 264	$ 19	$ 115	R 42