Derivative Instruments - Notional Values and Net Fair Value of Outstanding Contracts (Details) - Foreign Exchange Forward € in Millions, ¥ in Millions, ¥ in Millions, £ in Millions, R in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions	Dec. 31, 2019 USD ($)	Dec. 31, 2019 GBP (£)	Dec. 31, 2019 CAD ($)	Dec. 31, 2019 AUD ($)	Dec. 31, 2019 JPY (¥)	Dec. 31, 2019 MXN ($)	Dec. 31, 2019 CNY (¥)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 SGD ($)	Dec. 31, 2019 ZAR (R)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 GBP (£)	Dec. 31, 2018 CAD ($)	Dec. 31, 2018 AUD ($)	Dec. 31, 2018 JPY (¥)	Dec. 31, 2018 MXN ($)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 EUR (€)	Dec. 31, 2018 SGD ($)	Dec. 31, 2018 ZAR (R)
Derivative [Line Items]
Net fair value of assets of outstanding contracts | $	$ 0										$ 1
US Dollar
Derivative [Line Items]
Notional balance of outstanding contracts:		£ 14	$ 1	$ 42	¥ 264	$ 115	¥ 0	€ 36	$ 19	R 42		£ 1	$ 6	$ 47	¥ 396	$ 225	¥ 71	€ 45	$ 7	R 42
Euro
Derivative [Line Items]
Notional balance of outstanding contracts: | £		£ 0										£ 6