Net Income (Loss) Per Share (Computation Of Basic Earnings And Diluted Earnings Per Share) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Mar. 31, 2014		Dec. 31, 2013		Sep. 30, 2013		Jun. 30, 2013		Mar. 31, 2013		Dec. 31, 2012		Sep. 30, 2012		Jun. 30, 2012		Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2012
Earnings Per Share Reconciliation [Abstract]
Net income (loss)	$ 367	[1]	$ (308)	[2]	$ (273)	[3]	$ 222	[4]	$ 323	[5]	$ (45)	[6]	$ (381)	[7]	$ 201	[8]	$ 8	$ 98	$ 76
Weighted-average common stock outstanding - basic																	308	310	331
Dilutive potential common shares																	8	3	5
Weighted-average common stock outstanding - diluted																	316	313	336
Basic	$ 1.18		$ (1.00)		$ (0.89)		$ 0.73		$ 1.07		$ (0.15)		$ (1.21)		$ 0.63		$ 0.03	$ 0.32	$ 0.23
Diluted	$ 1.15		$ (1.00)		$ (0.89)		$ 0.71		$ 1.05		$ (0.15)		$ (1.21)		$ 0.63		$ 0.03	$ 0.31	$ 0.23

[1] Net income includes restructuring charges of $1 million and $2 million of acquisition-related contingent consideration, both of which are pre-tax amounts.

[2] Net loss includes pre-tax restructuring charges of $(1) million.

[3] Net loss includes restructuring charges of $(2) million and $(44) million of acquisition-related contingent consideration, both of which are pre-tax amounts.

[4] Net income includes restructuring charges of $1 million and $7 million of acquisition-related contingent consideration, both of which are pre-tax amounts.

[5] Net income includes $31 million of impairment charges on acquisition-related intangible assets, $(25) million of gain on strategic investments, net, and $1 million of acquisition-related contingent consideration, both of which are pre-tax amounts.

[6] Net loss includes $(45) million of acquisition-related contingent consideration, $(14) million gain on strategic investments, net, $6 million of impairment charges on acquisition-related intangible assets, and restructuring charges of $2 million, all of which are pre-tax amounts.

[7] Net loss includes pre-tax restructuring charges of $(2) million.

[8] Net income includes restructuring charges of $27 million and $(20) million of acquisition-related contingent consideration, both of which are pre-tax amounts.