Quarterly Financial And Market Information (Summary Of Quarterly Financial And Market Information) (Details) (USD $)
In Millions, except Per Share data, unless otherwise specified
 3 Months Ended 12 Months Ended
Mar. 31, 2015
Dec. 31, 2014
Sep. 30, 2014
Jun. 30, 2014
Mar. 31, 2014
Dec. 31, 2013
Sep. 30, 2013
Jun. 30, 2013
Mar. 31, 2015
Mar. 31, 2014
Mar. 31, 2013
Quarterly Financial And Market Information [Line Items]                      
Net revenue $ 1,185 $ 1,126 $ 990 $ 1,214 $ 1,123 $ 808 $ 695 $ 949 $ 4,515 $ 3,575 $ 3,797
Gross profit 951 725 563 847 900 291 282 755 3,086 2,228 2,409
Operating income (loss) 400 162 24 362 344 (292) (252) 233 948 33 121
Net income (loss) 395 [1] 142 3 [1] 335 [1] 367 [2] (308) [3] (273) [4] 222 [5] 875 8 98
Net income (loss) per share - Basic $ 1.27 $ 0.46 $ 0.01 $ 1.07 $ 1.18 $ (1.00) $ (0.89) $ 0.73 $ 2.81 $ 0.03 $ 0.32
Net income (loss) per share - Diluted $ 1.19 $ 0.44 $ 0.01 $ 1.04 $ 1.15 $ (1.00) $ (0.89) $ 0.71 $ 2.69 $ 0.03 $ 0.31
High price, Common stock per share $ 58.24 $ 48.33 $ 38.42 $ 37.15 $ 30.25 $ 26.44 $ 27.99 $ 23.61 $ 58.24 $ 30.25  
Low price, Common stock per share $ 45.96 $ 32.62 $ 33.31 $ 26.67 $ 21.54 $ 20.97 $ 23.18 $ 16.91 $ 26.67 $ 16.91  
Acquisition-related contingent consideration (1)   (1) (1)     (44) 7 (3) (35) (64)
Restructuring Charges         1 (1) (2) 1 0 (1) 27
Gains on strategic investments, net       $ (1) $ 2       $ 0 $ 0 $ 39
[1] Net income includes $(1) million of acquisition-related contingent consideration, of which is pre-tax amounts.
[2] Net income includes restructuring charges of $1 million and $2 million of acquisition-related contingent consideration, both of which are pre-tax amounts.
[3] Net loss includes pre-tax restructuring charges of $(1) million.
[4] Net loss includes restructuring charges of $(2) million and $(44) million of acquisition-related contingent consideration, both of which are pre-tax amounts.
[5] Net income includes restructuring charges of $1 million and $7 million of acquisition-related contingent consideration, both of which are pre-tax amounts.