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Amount, after tax, of reclassification from accumulated other comprehensive income (AOCI) of gain (loss) from increase (decrease) in fair value of net investment hedge.

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Financial Instruments - (Narratives) (Details)	3 Months Ended
Financial Instruments - (Narratives) (Details)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Mar. 31, 2021 GBP (£)	Mar. 31, 2021 EUR (€)	Dec. 31, 2020 USD ($)	Dec. 31, 2020 GBP (£)	Dec. 31, 2020 EUR (€)
Net investment hedges \| Senior Euro Notes Maturing Two Thousand Twenty Two To Two Thousand Thirty Nine and ECP Notes \| Senior notes
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives
Notional amount \| €				€ 6,968,000,000			€ 7,466,000,000
Net investment hedges \| Senior EURO Floating Rate Notes And Senior Euro Notes Maturing Two Thousand Twenty One \| Senior notes
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives
Notional amount \| €							1,000,000,000
Net investment hedges \| Sterling senior notes due 2022 to 2031 \| Senior notes
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives
Notional amount \| £			£ 1,203,000,000			£ 1,850,000,000
Interest rate swap \| Fair value hedging
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives
Notional amount	$ 1,604,000,000		925,000,000	500,000,000	$ 1,000,000,000		500,000,000
Interest rate swap \| Fair value hedging \| 1.1% Euro senior notes due July 2024 \| Senior notes
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives
Derivative asset fair value	96,000,000				10,000,000
Interest rate swap \| Net investment hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives
Derivative asset fair value, gross liability	(206,000,000)				$ (306,000,000)
Currency forward contract \| Net investment hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives
Gain (loss) for the change in fair value on derivative used in net investment hedge, after tax, recorded in other comprehensive earnings loss	$ 321,000,000	$ 535,000,000
Currency swap \| Net investment hedges
Reclassification Adjustment out of Accumulated Other Comprehensive Income on Derivatives
Notional amount			£ 2,045,000,000	€ 5,906,000,000		£ 565,000,000	€ 4,508,000,000