Fair Value Measurements (Financial Instruments Measured At Fair Value Using Significant Unobservable Inputs) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014		Mar. 31, 2013		Dec. 31, 2013		Dec. 31, 2012
Equity Securities [Member]
Schedule Of Fair Value Measurements [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	$ 0		$ 0
Balance- Beginning of Period, Assets	4		3
Transfers out of Level 3, Assets	(2)		(1)
Change in Net Unrealized Gains (Losses) included in OCI, Assets	1		0
Net Realized Gains/Losses, Assets			0
Purchases, Assets	1		0
Sales, Assets	(2)		0
Settlements, Assets			0
Balance-End of Period, Assets	2		2
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets			0
Short-term Investments [Member]
Schedule Of Fair Value Measurements [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0
Balance- Beginning of Period, Assets	7
Transfers out of Level 3, Assets	(7)
Purchases, Assets	0
Balance-End of Period, Assets	0
Other Long-term Investments [Member]
Schedule Of Fair Value Measurements [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0
Balance- Beginning of Period, Assets	2,440		2,252
Transfers out of Level 3, Assets			0
Change in Net Unrealized Gains (Losses) included in OCI, Assets	41		22
Net Realized Gains/Losses, Assets	0		(1)
Purchases, Assets	200		136
Sales, Assets	(1)		(9)
Settlements, Assets	(69)		(72)
Balance-End of Period, Assets	2,611		2,328
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Assets	0		(1)
Available-for-sale Securities [Member] | Foreign [Member]
Schedule Of Fair Value Measurements [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		3
Balance- Beginning of Period, Assets	44		60
Transfers out of Level 3, Assets	(18)		(27)
Change in Net Unrealized Gains (Losses) included in OCI, Assets	(1)		0
Net Realized Gains/Losses, Assets	0		1
Purchases, Assets	2		0
Sales, Assets	(1)		(1)
Settlements, Assets	0		(1)
Balance-End of Period, Assets	26		35
Available-for-sale Securities [Member] | Corporate Debt Securities [Member]
Schedule Of Fair Value Measurements [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	4		12
Balance- Beginning of Period, Assets	166		102
Transfers out of Level 3, Assets	(22)		(2)
Change in Net Unrealized Gains (Losses) included in OCI, Assets	0		1
Net Realized Gains/Losses, Assets	0		0
Purchases, Assets	15		10
Sales, Assets	(6)		0
Settlements, Assets	(6)		(5)
Balance-End of Period, Assets	151		118
Available-for-sale Securities [Member] | Mortgage Backed-Securities [Member]
Schedule Of Fair Value Measurements [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Asset Transfers Into Level 3	0		0
Balance- Beginning of Period, Assets	8		13
Transfers out of Level 3, Assets	0		0
Change in Net Unrealized Gains (Losses) included in OCI, Assets			0
Net Realized Gains/Losses, Assets			0
Purchases, Assets	0		0
Sales, Assets	0		0
Settlements, Assets	0		0
Balance-End of Period, Assets	8		13
Guaranteed Minimum Income Benefit [Member]
Schedule Of Fair Value Measurements [Line Items]
Fair Value, Measurement with Unobservable Inputs Reconciliations, Recurring Basis, Liability Value	243	[1]	753	[1]	193	[1]	1,119	[1]
Fair Value, Measurement with Unobservable Inputs Reconciliation, Recurring Basis, Liability, Gain (Loss) Included in Earnings	50	[1]	(366)	[1]
Net Realized Gains/Losses Attributable to Changes in Fair Value at the Balance Sheet Date, Liabilities	50		(366)
Reported liabilities	$ 483		$ 1,000		$ 427		$ 1,400

[1] Our GLB reinsurance product meets the definition of a derivative instrument for accounting purposes and is accordingly carried at fair value. Excluded from the table above is the portion of the GLB derivative liability classified as Future policy benefits in the consolidated balance sheets. Refer to Note 5 for additional information.