Derivative Instruments - Notional Values and Net Fair Value of Outstanding Contracts (Details) - Foreign Exchange Forward € in Millions, ¥ in Millions, ¥ in Millions, £ in Millions, kr in Millions, R$ in Millions, Kč in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions, $ in Millions	Dec. 31, 2018 CZK (Kč)	Dec. 31, 2018 SEK (kr)	Dec. 31, 2018 USD ($)	Dec. 31, 2018 CAD ($)	Dec. 31, 2018 AUD ($)	Dec. 31, 2018 JPY (¥)	Dec. 31, 2018 GBP (£)	Dec. 31, 2018 MXN ($)	Dec. 31, 2018 CNY (¥)	Dec. 31, 2018 EUR (€)	Dec. 31, 2018 BRL (R$)	Dec. 31, 2018 SGD ($)	Dec. 31, 2017 CZK (Kč)	Dec. 31, 2017 SEK (kr)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 CAD ($)	Dec. 31, 2017 AUD ($)	Dec. 31, 2017 JPY (¥)	Dec. 31, 2017 GBP (£)	Dec. 31, 2017 MXN ($)	Dec. 31, 2017 CNY (¥)	Dec. 31, 2017 EUR (€)	Dec. 31, 2017 BRL (R$)	Dec. 31, 2017 SGD ($)
Derivative [Line Items]
Net fair value of asset (liability) outstanding contracts | $			$ 1												$ (2)
US Dollar
Derivative [Line Items]
Notional balance of outstanding contracts:	Kč 0	kr 0	$ 42	$ 6	$ 47	¥ 396	£ 1	$ 225	¥ 71	€ 45	R$ 0	$ 7	Kč 361	kr 13	$ 0	$ 12	$ 55	¥ 151	£ 13	$ 0	¥ 0	€ 108	R$ 34	$ 4
Euro
Derivative [Line Items]
Notional balance of outstanding contracts: | £							£ 6												£ 5