Schedule II - Condensed Financial Information, Debt Issuances (Details) (USD $) In Millions, unless otherwise specified			0 Months Ended			0 Months Ended			0 Months Ended			1 Months Ended			1 Months Ended					0 Months Ended			0 Months Ended			0 Months Ended			1 Months Ended			1 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Nov. 10, 2011 Notes due 2016 2.75% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Notes due 2016 2.75% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Notes due 2016 2.75% Interest [Member] Uncollateralized Debt [Member]	Nov. 10, 2011 Notes due 2022 4% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Notes due 2022 4% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Notes due 2022 4% Interest [Member] Uncollateralized Debt [Member]	Nov. 10, 2011 Notes due 2042 5.375% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Notes due 2042 5.375% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Notes due 2042 5.375% Interest [Member] Uncollateralized Debt [Member]	Mar. 31, 2011 Notes Due 2021 4.5% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Notes Due 2021 4.5% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Notes Due 2021 4.5% Interest [Member] Uncollateralized Debt [Member]	Mar. 31, 2011 Notes Due 2041 5.875% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Notes Due 2041 5.875% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Notes Due 2041 5.875% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Parent Company [Member]	Dec. 31, 2012 Parent Company [Member]	Nov. 10, 2011 Parent Company [Member] Notes due 2016 2.75% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Parent Company [Member] Notes due 2016 2.75% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Parent Company [Member] Notes due 2016 2.75% Interest [Member] Uncollateralized Debt [Member]	Nov. 10, 2011 Parent Company [Member] Notes due 2022 4% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Parent Company [Member] Notes due 2022 4% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Parent Company [Member] Notes due 2022 4% Interest [Member] Uncollateralized Debt [Member]	Nov. 10, 2011 Parent Company [Member] Notes due 2042 5.375% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Parent Company [Member] Notes due 2042 5.375% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Parent Company [Member] Notes due 2042 5.375% Interest [Member] Uncollateralized Debt [Member]	Mar. 31, 2011 Parent Company [Member] Notes Due 2021 4.5% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Parent Company [Member] Notes Due 2021 4.5% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Parent Company [Member] Notes Due 2021 4.5% Interest [Member] Uncollateralized Debt [Member]	Mar. 31, 2011 Parent Company [Member] Notes Due 2041 5.875% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2013 Parent Company [Member] Notes Due 2041 5.875% Interest [Member] Uncollateralized Debt [Member]	Dec. 31, 2012 Parent Company [Member] Notes Due 2041 5.875% Interest [Member] Uncollateralized Debt [Member]
Debt Instrument [Line Items]
Long-term debt, face value			$ 600			$ 750			$ 750			$ 300			$ 300					$ 600			$ 750			$ 750			$ 300			$ 300
Long-term debt, net of discount	$ 5,014	$ 4,986	$ 600	$ 600	$ 600	$ 743	$ 744	$ 743	$ 750	$ 750	$ 750	$ 298	$ 299	$ 299	$ 298	$ 298	$ 298	$ 4,871	$ 4,870	$ 600	$ 600	$ 600	$ 743	$ 744	$ 743	$ 750	$ 750	$ 750	$ 298	$ 299	$ 299	$ 298	$ 298	$ 298
Stated interest rate			2.75%	2.75%	2.75%	4.00%	4.00%	4.00%	5.375%	5.375%	5.375%	4.50%	4.50%	4.50%	5.875%	5.875%	5.875%			2.75%			4.00%			5.375%			4.50%			5.875%
Effective interest rate			2.936%			4.346%			5.542%			4.683%			6.008%					2.93%			4.346%			5.542%			4.683%			6.008%
Percentage of principal amount to be paid upon redemption			100.00%			100.00%			100.00%			100.00%			100.00%					100.00%			100.00%			100.00%			100.00%			100.00%
Basis Points Added To Treasury Rate			0.30%			0.35%			0.40%			0.20%			0.25%					0.30%			0.35%			0.40%			0.20%			0.25%