Changes, net of tax, in accumulated other comprehensive loss, were as follows: | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currency Translation Adjustments | | | | | | | | | | | | | Other Currency | | | | Accumulated Other | | | Cash Flow | | Net Investment | | Translation | | | | Comprehensive | (MILLIONS OF DOLLARS) | | Hedges | | Hedges | | Adjustments | | Benefit Plans | | Loss | Balance, December 31, 2018 | | $ | (4) | | | $ | 10 | | | $ | (621) | | | $ | (14) | | | $ | (629) | | Other comprehensive income, net of tax | | — | | | 8 | | | 23 | | | — | | | 31 | | | | | | | | | | | | | Balance, March 31, 2019 | | $ | (4) | | | $ | 18 | | | $ | (598) | | | $ | (14) | | | $ | (598) | | | | | | | | | | | | | Balance, December 31, 2019 | | $ | — | | | $ | 21 | | | $ | (724) | | | $ | (23) | | | $ | (726) | | Other comprehensive (loss)/income, net of tax | | (28) | | | 17 | | | (44) | | | — | |
| (55) | | | | | | | | | | | | | Balance, March 31, 2020 | | $ | (28) | | | $ | 38 | | | $ | (768) | | | $ | (23) | | | $ | (781) | |
|