Fair Value Measurements And Disclosure (Fair Value Leveling) (Details) - USD ($) $ in Millions	Mar. 31, 2019	Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities Debt Securities	$ 989	$ 870
Securities Investment [Member] | United States [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	1,092	1,061
Securities Investment [Member] | Non-US [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	263	256
Fixed Income Bonds [Member] | United States [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	208	172
Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	2	0
Liability Derivatives (at fair value)	(13)	(39)
Cross-Currency Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	427	472
Liability Derivatives (at fair value)	(2,697)	(2,563)
Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	87	87
Liability Derivatives (at fair value)	(6)	(2)
Level 1 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities Debt Securities	0	0
Level 1 [Member] | Securities Investment [Member] | United States [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	1,092	1,061
Level 1 [Member] | Securities Investment [Member] | Non-US [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	263	256
Level 1 [Member] | Fixed Income Bonds [Member] | United States [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	208	172
Level 1 [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 1 [Member] | Cross-Currency Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 1 [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities Debt Securities	989	870
Level 2 [Member] | Securities Investment [Member] | United States [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	0	0
Level 2 [Member] | Securities Investment [Member] | Non-US [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	0	0
Level 2 [Member] | Fixed Income Bonds [Member] | United States [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	0	0
Level 2 [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	2	0
Liability Derivatives (at fair value)	(13)	(39)
Level 2 [Member] | Cross-Currency Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	427	472
Liability Derivatives (at fair value)	(2,697)	(2,563)
Level 2 [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	87	87
Liability Derivatives (at fair value)	(6)	(2)
Level 3 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Available-for-sale Securities Debt Securities	0	0
Level 3 [Member] | Securities Investment [Member] | United States [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	0	0
Level 3 [Member] | Securities Investment [Member] | Non-US [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	0	0
Level 3 [Member] | Fixed Income Bonds [Member] | United States [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Equity Securities (at fair value)	0	0
Level 3 [Member] | Interest Rate Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 3 [Member] | Cross-Currency Swaps [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	0	0
Level 3 [Member] | Foreign Exchange Contracts [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Asset Derivatives (at fair value)	0	0
Liability Derivatives (at fair value)	$ 0	$ 0