Financing (Commercial Paper Programs And Credit Facilities) (Narrative) (Details) € in Millions		12 Months Ended
	Dec. 31, 2020 EUR (€)	Dec. 31, 2020 EUR (€)	Dec. 31, 2020 USD ($)	Jul. 03, 2020 USD ($)	Dec. 31, 2019 EUR (€)	Dec. 31, 2019 USD ($)	Dec. 31, 2015 USD ($)
Line of Credit Facility [Line Items]
Debt discounts, premiums and debt issuance costs			$ 132,000,000			$ 112,000,000
Long-term debt			$ 21,204,000,000			21,729,000,000
Euro-denominated commercial paper | Commercial paper
Line of Credit Facility [Line Items]
Debt, weighted average annual interest rate, basis points	(0.05%)	(0.05%)	(0.05%)
Long-term debt weighted average maturity	25 days
Long-term debt, commerical paper			$ 611,000,000
Long-term debt	€ 500	€ 500	611,000,000		€ 4,600	5,146,000,000
0.352% senior unsecured notes due 2021 | Senior notes
Line of Credit Facility [Line Items]
Long-term debt			290,000,000			276,000,000
Revolving credit facility | Superseded Credit Facility | Long-term debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity							$ 4,000,000,000.0
Revolving credit facility | Five-Year Facility | Long-term debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity						5,000,000,000.0
Additional borrowing capacity						2,500,000,000
Credit facility, borrowings outstanding			$ 0
Revolving credit facility | Five-Year Facility | Long-term debt | Federal funds rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		0.50%
Revolving credit facility | Five-Year Facility | Long-term debt | Eurodollar
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		1.00%
Revolving credit facility | Five-Year Facility | Minimum | Long-term debt
Line of Credit Facility [Line Items]
Commitment fee, percent		0.04%
Debt instrument, covenants, leverage ratio	0.65	0.65	0.65
Revolving credit facility | Five-Year Facility | Minimum | Long-term debt | LIBOR-based rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		0.585%
Revolving credit facility | Five-Year Facility | Maximum | Long-term debt
Line of Credit Facility [Line Items]
Commitment fee, percent		0.125%
Debt instrument, covenants, leverage ratio	1.00	1.00	1.00
Revolving credit facility | Five-Year Facility | Maximum | Long-term debt | LIBOR-based rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		1.00%
Revolving credit facility | Superseded 364-Day Facility | Short-term debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity						$ 5,000,000,000.0
Revolving credit facility | Superseded 364-Day Facility | Short-term debt | Federal funds rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		0.50%
Revolving credit facility | Superseded 364-Day Facility | Short-term debt | Eurodollar
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		1.00%
Revolving credit facility | Superseded 364-Day Facility | Minimum | Short-term debt
Line of Credit Facility [Line Items]
Commitment fee, percent		0.03%
Revolving credit facility | Superseded 364-Day Facility | Minimum | Short-term debt | LIBOR-based rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		0.595%
Revolving credit facility | Superseded 364-Day Facility | Maximum | Short-term debt
Line of Credit Facility [Line Items]
Commitment fee, percent		0.05%
Revolving credit facility | Superseded 364-Day Facility | Maximum | Short-term debt | LIBOR-based rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		1.005%
Revolving credit facility | Superseded 364-Day Facility | Maximum | Short-term debt | Eurodollar
Line of Credit Facility [Line Items]
Commitment fee, percent		0.005%
Revolving credit facility | Terminated 364-Day Credit Facility | Short-term debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity			$ 2,500,000,000
Revolving credit facility | Terminated 364-Day Credit Facility | Short-term debt | Federal funds rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		0.50%
Revolving credit facility | Terminated 364-Day Credit Facility | Short-term debt | Eurodollar
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		1.00%
Revolving credit facility | Terminated 364-Day Credit Facility | Minimum | Short-term debt
Line of Credit Facility [Line Items]
Commitment fee, percent		0.10%
Revolving credit facility | Terminated 364-Day Credit Facility | Minimum | Short-term debt | LIBOR-based rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		0.90%
Revolving credit facility | Terminated 364-Day Credit Facility | Minimum | Short-term debt | Eurodollar
Line of Credit Facility [Line Items]
Commitment fee, percent		0.00%
Revolving credit facility | Terminated 364-Day Credit Facility | Maximum | Short-term debt
Line of Credit Facility [Line Items]
Commitment fee, percent		0.225%
Revolving credit facility | Terminated 364-Day Credit Facility | Maximum | Short-term debt | LIBOR-based rate
Line of Credit Facility [Line Items]
Basis spread percentage to determine floating interest rate		1.275%
Revolving credit facility | Terminated 364-Day Credit Facility | Maximum | Short-term debt | Eurodollar
Line of Credit Facility [Line Items]
Commitment fee, percent		0.275%
Revolving credit facility | 364-Day Facility | Short-term debt
Line of Credit Facility [Line Items]
Line of credit, maximum borrowing capacity				$ 2,500,000,000