Fair Value Measurements (Unrealized Losses And Fair Value Of Investments With Unrealized Losses) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	393
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	409
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	$ 987
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	1,081
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	1
Asset-backed Securities [Member]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	225
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	233
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	397
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	397
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than 12 Months, Aggregate Loss	1
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	1
Foreign Government Debt Securities [Member]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	45
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	52
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	100
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	194
Available-for-sale Securities, Continuous Unrealized Loss Position, Aggregate Loss	0
US Government Agencies Debt Securities [Member]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	37
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	37
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	178
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	178
Other Debt Obligations [Member]
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions, Less than One Year	86
Available-for-sale, Securities in Unrealized Loss Positions, Qualitative Disclosure, Number of Positions	87
Available-for-sale Securities, Continuous Unrealized Loss Position, Less than Twelve Months, Fair Value	312
Available-for-sale Securities, Continuous Unrealized Loss Position, Fair Value	$ 312