Fair Value Measurements (Valuation Of Financial Instruments By Pricing Categories) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013	Dec. 31, 2012
Cash and Cash Equivalents, Fair Value Disclosure	$ 1,356	$ 1,339
Investments, Fair Value Disclosure	4,775	4,077
Derivative Asset	21	25
Liabilities:	77	72
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	45	59
Liabilities, Fair Value Disclosure, Recurring	151	133
Available-for-sale Securities [Member]
Investments, Fair Value Disclosure	3,321	2,641
Available-for-sale Securities [Member] | Corporate and asset-backed debt securities
Investments, Fair Value Disclosure	1,614	1,177
Available-for-sale Securities [Member] | Foreign Government Debt Securities [Member]
Investments, Fair Value Disclosure	828	845
Available-for-sale Securities [Member] | US Government Agencies Debt Securities [Member]
Investments, Fair Value Disclosure	361	211
Available-for-sale Securities [Member] | US Treasury Securities [Member]
Investments, Fair Value Disclosure	408	350
Available-for-sale Securities [Member] | Certificates of Deposit [Member]
Investments, Fair Value Disclosure	103	53
Available-for-sale Securities [Member] | Other Security Investments [Member]
Investments, Fair Value Disclosure	7	5
Trading Securities [Member]
Investments, Fair Value Disclosure	77	72
Fair Value, Inputs, Level 1 [Member]
Cash and Cash Equivalents, Fair Value Disclosure	1,356	1,339
Investments, Fair Value Disclosure	1,433	1,411
Liabilities:	77	72
Liabilities, Fair Value Disclosure, Recurring	77	72
Fair Value, Inputs, Level 1 [Member] | Trading Securities [Member]
Investments, Fair Value Disclosure	77	72
Fair Value, Inputs, Level 2 [Member]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Investments, Fair Value Disclosure	3,342	2,666
Derivative Asset	21	25
Liabilities, Fair Value Disclosure, Recurring	29	2
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member]
Investments, Fair Value Disclosure	3,321	2,641
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member] | Corporate and asset-backed debt securities
Investments, Fair Value Disclosure	1,614	1,177
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member] | Foreign Government Debt Securities [Member]
Investments, Fair Value Disclosure	828	845
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member] | US Government Agencies Debt Securities [Member]
Investments, Fair Value Disclosure	361	211
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member] | US Treasury Securities [Member]
Investments, Fair Value Disclosure	408	350
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member] | Certificates of Deposit [Member]
Investments, Fair Value Disclosure	103	53
Fair Value, Inputs, Level 2 [Member] | Available-for-sale Securities [Member] | Other Security Investments [Member]
Investments, Fair Value Disclosure	7	5
Fair Value, Inputs, Level 3 [Member]
Cash and Cash Equivalents, Fair Value Disclosure	0	0
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Value	45	59	103
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Gain (Loss) Included in Earnings		5
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset and Liability, Settlements	14	39
Liabilities, Fair Value Disclosure, Recurring	45	59
Interest Rate Swap [Member]
Derivative Liability	6
Interest Rate Swap [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Liability	6
Foreign Exchange [Member]
Derivative Liability	23	2
Foreign Exchange [Member] | Fair Value, Inputs, Level 2 [Member]
Derivative Liability	$ 23	$ 2