Fair Value Measurements Fair Value Measurements (Schedule of Cash and Cash Equivalents and Investments) (Details) - USD ($) $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	$ 891	$ 1,391	$ 581	$ 1,025
Short-term Investments	1,733	0
Long-term Investments	319	$ 0
Cash, Cash Equivalents, and Short-term Investments	2,943
Cash and Cash Equivalents [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	891
Short-term Investments	0
Long-term Investments	0
Cash, Cash Equivalents, and Short-term Investments	891
Commercial Paper [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	0
Short-term Investments	742
Long-term Investments	0
Cash, Cash Equivalents, and Short-term Investments	742
Corporate Bond Securities [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	0
Short-term Investments	459
Long-term Investments	319
Cash, Cash Equivalents, and Short-term Investments	778
Bank Time Deposits [Member]
Schedule of Held-to-maturity Securities [Line Items]
Cash and cash equivalents, at Carrying Value	0
Short-term Investments	532
Long-term Investments	0
Cash, Cash Equivalents, and Short-term Investments	$ 532